Grade 5 Math Unit 1

Grade 5 Maths โ€“ Unit 1 Notes
๐Ÿ“š Grade 4 Maths
Unit 1: Place Value within 1,000,000
Lessons 1 โ€“ 8  |  Complete Study Notes
โœ๏ธ Lesson 1: Roman Numerals
โœ๏ธ Lesson 2: Numbers to 10,000
โœ๏ธ Lesson 3: Numbers to 100,000
โœ๏ธ Lesson 4: Numbers to 1,000,000
โœ๏ธ Lesson 5: Read & Write 5- and 6-digit Numbers
โœ๏ธ Lesson 6: Powers of 10
โœ๏ธ Lesson 7: 10/100/1,000/10,000/100,000 More or Less
โœ๏ธ Lesson 8: Partition Numbers to 1,000,000
Cover
Lesson 1 โ€” Roman Numerals
๐Ÿ”‘ Key Roman Numeral Values (MEMORISE THESE!)
Number1510501005001,000
RomanIVXLCDM
๐Ÿ“ Rules for Writing Roman Numerals
  • Write symbols from largest to smallest (left โ†’ right)
  • Add values when a smaller symbol comes AFTER a larger one  →  VI = 6
  • Subtract when a smaller symbol comes BEFORE a larger one  →  IV = 4
  • Never repeat I, X, C, M more than 3 times in a row
  • Key subtractive pairs: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900
Q1 โ€” Write these numbers in Roman Numerals
  • 12 = XII    (10 + 1 + 1)
  • 35 = XXXV    (10+10+10+5)
  • 43 = XLIII    (50โˆ’10 + 1+1+1)
  • 90 = XC    (100โˆ’10)
  • 114 = CXIV    (100 + 10 + (5โˆ’1))
Q2 โ€” Multiples of 100 in Roman Numerals
  • 100 = C
  • 200 = CC
  • 300 = CCC
  • 400 = CD  (500โˆ’100)
  • 500 = D
  • 600 = DC
  • 700 = DCC
  • 800 = DCCC
  • 900 = CM  (1000โˆ’100)
  • 1,000 = M
Q3 โ€” Fill in missing numbers
  • MMCXI = 1000 + 1000 + 100 + 10 + 1 = 2,111
  • DCCL = 500 + 100 + 100 + 50 = 750
  • CXCV = 100 + 100 โˆ’ 10 + 5 = 195
Q4 โ€” Part-Whole Models
a) CDLXX = 470
  • CD = 400
  • LXX = 70
  • 400 + 70 = 470 โœ“
b) MXLVII = 1047
  • M = 1,000
  • XL = 40
  • VII = 7
  • 1000+40+7 = 1,047 โœ“
Q5 โ€” Match Coins to Years
  • MCCXI โ†’ 1211
  • MDXLV โ†’ 1545
  • MCDLXI โ†’ 1461
  • MCMI โ†’ 1901
How to decode MCMI:
M=1000, CM=900, I=1 โ†’ 1000+900+1 = 1901
Q6 โ€” Is Lexi correct? (MCX vs CMX)
  • MCX = 1000 + 100 + 10 = 1,110
  • CMX = 1000 โˆ’ 100 + 10 = 910
โŒ Lexi is NOT correct. The ORDER of letters matters! MCX โ‰  CMX even though they use the same letters.
Q7 โ€” Complete using Roman Numerals
  • 10 years earlier than 1985 โ†’ 1975 = MCMLXXV
  • 100 years later than 1480 โ†’ 1580 = MDLXXX
  • 50 years later than 1962 โ†’ 2012 = MMXII
Working out MCMLXXV (1975):
M(1000) + CM(900) + L(50) + XX(20) + V(5) = 1975 โœ“
๐Ÿ† Challenge Q8 โ€” Descending order using V, X, L, C, D

The column must go in descending order. Work out each value:

  • MDCLIX โ†’ L=50  โ†’  1659
  • MCDVI โ†’ D=500  โ†’  1506
  • DCCLX โ†’ X=10  โ†’  760
  • CDXXI โ†’ C=100  โ†’  521
  • CCCXV โ†’ V=5  โ†’  395

Cards used in order: L, D, X, C, V

๐Ÿ“Œ Reflect โ€” Key facts to remember
M = 1,000  |  D = 500  |  L = 50
MDXL = 1000+500+40 = 1,540 (because XL = 50โˆ’10 = 40)
Page 1 โ€” Roman Numerals
Lesson 2 โ€” Numbers to 10,000
๐Ÿ”‘ Place Value Columns (4-digit numbers)
Th
H
T
O
Thousands
Hundreds
Tens
Ones
1,000s
100s
10s
1s
Q1 โ€” Read the place value counters
  • a) 1 Th + 2 H + 5 T + 3 O = 1,253
  • b) 3 Th + 2 H + 2 T + 6 O = 3,226  (Note: 7 ones shown โ†’ 6 ones written, slight mark in book, answer is 3,226)
  • c) 2 Th + 6 H + 0 T + 5 O = 2,605
  • d) 3 Th + 0 H + 0 T + 5 O = 3,005
  • e) Part-whole: 2,000 + 800 + 20 + 4 = 2,824
๐Ÿ’ก How to read place value counters
Count how many counters are in each column. Multiply by the column value.
E.g. 3 counters in the Hundreds column = 3 ร— 100 = 300
Q2 โ€” Draw counters for 5,632 & partition
  • Th column: 5 counters (5 ร— 1,000)
  • H column: 6 counters (6 ร— 100)
  • T column: 3 counters (3 ร— 10)
  • O column: 2 counters (2 ร— 1)
5,632 = 5,000 + 600 + 30 + 2
Q3 โ€” Value of each underlined digit
  • 1,794 โ†’ 9 is in the Tens column โ†’ 90
  • 6,480 โ†’ 4 is in the Hundreds column โ†’ 400
  • 2,058 โ†’ 2 is in the Thousands column โ†’ 2,000
Q4 โ€” Read the representations
  • a) Abacus (5 Th, 3 H, 5 T, 6 O) = 5,356
  • b) Part-whole: 2,000 + 100 + 0 + 5 = 2,105
  • c) Counter grid (1000+10+1000+1 / 1+10+100+10 / 1+100+1000 / 1+1000+1) = 4,235
For counter grids:
Add up ALL counters of each type across the whole grid, then put them in the right column.
๐Ÿ† Challenge Q5 โ€” Digit cards 0, 2, 5, 8
  • a) A number with 5 hundreds โ†’ 2,508 or 8,502 etc.
  • b) A number that is odd (ends in odd digit: 5) โ†’ 2,805
  • c) Where 2 has value of 20 (2 in tens column) โ†’ 8,025
  • d) Largest possible even number (arrange largest first, must end in even) โ†’ 8,520
๐Ÿ’ก For largest even: try 8,520 โ†’ ends in 0 (even) โœ“ and is the largest possible arrangement!
๐Ÿ“Œ Reflect โ€” Describe a 4-digit number
When you make a number from dice, describe it using:
โ†’ How many thousands? How many hundreds? Tens? Ones?
โ†’ What does each digit represent? (e.g. the 6 in 6,345 = 6,000)
Page 2 โ€” Numbers to 10,000
Lesson 3 โ€” Numbers to 100,000
๐Ÿ”‘ 5-Digit Place Value Columns
TTh
Th
H
T
O
Ten Thous.
Thousands
Hundreds
Tens
Ones
10,000s
1,000s
100s
10s
1s
Q1 โ€” Number 85,013
TTh=8, Th=5, H=0, T=1, O=3
  • What does digit 5 represent? โ†’ 5 thousands = 5,000
  • What does digit 1 represent? โ†’ 1 ten = 10
  • What does digit 8 represent? โ†’ 8 ten thousands = 80,000
  • Digit in 100s position? โ†’ 0
b) Swap digits 5 and 8: New number = 58,013
In words: Fifty-eight thousand and thirteen
Q2 โ€” Match the value of digit 4
  • 43,250 โ†’ 4 is in TTh place โ†’ value = 40,000
  • 32,409 โ†’ 4 is in H place โ†’ value = 400
  • 34,250 โ†’ 4 is in Th place โ†’ value = 4,000
  • 23,546 โ†’ 4 is in T place โ†’ value = 40
Q3 โ€” Draw counters for 26,415
  • TTh: 2 counters (20,000)
  • Th: 6 counters (6,000)
  • H: 4 counters (400)
  • T: 1 counter (10)
  • O: 5 counters (5)
Q4 โ€” Complete part-whole models
  • a) 55,327 = 50,000 + 5,000 + 300 + 20 + 7
  • b) 12,300 = 10,000 + 2,000 + 300
  • c) 20,090 = 20,000 + 90
๐Ÿ’ก Tip for part-whole models:
Split the number by each place value. If a column is 0, you don’t need that branch!
E.g. 20,090 has 0 thousands, 0 hundreds, so only show 20,000 and 90.
Q5 โ€” More/Less than 13,572
  • a) 1,000 more than 13,572 = 14,572
  • b) 100 more than 13,572 = 13,672
  • c) 200 less than 13,572 = 13,372
  • d) 50,000 more than 13,572 = 63,572
๐Ÿ’ก Only the relevant digit changes! Adding 1,000 only changes the Thousands digit.
Adding 100 only changes the Hundreds digit (unless you need to regroup).
๐Ÿ“Œ Key vocabulary
Ten Thousands (TTh) โ€” the 5th digit from the right
Example: In 85,013 โ†’ the 8 is worth eighty thousand = 80,000
Remember: Zero as a placeholder is essential! 20,090 โ‰  2,090
Page 3 โ€” Numbers to 100,000
Lesson 4 โ€” Numbers to 1,000,000
๐Ÿ”‘ 6-Digit Place Value Columns
HTh
TTh
Th
H
T
O
Hundred
Thousands
Ten
Thousands
Thousands
Hundreds
Tens
Ones
100,000s
10,000s
1,000s
100s
10s
1s
Q1 โ€” Pencil boxes (each has 100,000)
  • 6 boxes ร— 100,000 = 600,000
  • In words: Six hundred thousand
Q2 โ€” What numbers are shown?
  • a) 5 ร— 100,000 counters = 500,000
  • b) 10 ร— 100,000 counters = 1,000,000
  • c) Grid: 1 HTh + 7 TTh + 2 Th + 3 H + 1 T + 5 O = 172,315
Q3 โ€” Number of views on a video: 123,419
In words: One hundred and twenty-three thousand, four hundred and nineteen
How to say 6-digit numbers:
Split at the comma: “123” + “419”
โ†’ Say “one hundred and twenty-three THOUSAND, four hundred and nineteen”
Q4 โ€” Draw 126,300 in place value grid
  • HTh: 1 counter (100,000)
  • TTh: 2 counters (20,000)
  • Th: 6 counters (6,000)
  • H: 3 counters (300)
  • T: 0 counters
  • O: 0 counters
Q5 โ€” Write in numerals
  • a) Three hundred and twenty-nine thousand and one hundred = 329,100
  • b) Six hundred thousand and forty = 600,040
  • c) Four hundred thousand, five hundred and ninety-six pounds = ยฃ400,596
Q6 โ€” What does the 4 represent?
  • a) 314,912 โ†’ 4 is in Thousands โ†’ 4,000
  • b) 240 โ†’ 4 is in Tens โ†’ 40
  • c) 500,240 โ†’ 4 is in Tens โ†’ 40
  • d) 77,314 โ†’ 4 is in Ones โ†’ 4
  • e) Four hundred and eight thousand, three hundred and one = 408,301 โ†’ 4 is in HTh โ†’ 400,000
๐Ÿ† Challenge Q7 โ€” Olivia’s number: 301,125

HTh=3, TTh=0, Th=1, H=1, T=2, O=5 (reading the counters)

She moves 2 counters so the number now has 1 thousand (Th column = 1).

The 2 moved counters can go to other columns. Five possible answers:

  • 301,125 โ€” move TTh counter โ†’ 311,025
  • 311,025, 310,125, 301,215, 302,115, 300,225 (any where Th=1)
Page 4 โ€” Numbers to 1,000,000
Lesson 5 โ€” Read & Write 5- and 6-Digit Numbers
๐Ÿ”‘ Commas in large numbers
We use a comma to separate thousands from hundreds:
  โ†’ 4-digit: 1,324    5-digit: 61,324    6-digit: 525,262
Count from the RIGHT โ€” comma goes after 3rd digit from right.
Q1 โ€” Read dice numbers (each die = one digit)
  • a) Dice show 1,3,2,4 โ†’ 1,324
  • b) Dice show 5,2,6,2 โ†’ 5,262
  • c) Dice show 6,1,3,2,4 โ†’ 61,324
  • d) Dice show 5,2,5,2,6,2 โ†’ 525,262
Q2 โ€” Arrange digit cards 9, 0, 9, 0, 0, 0 into 6-digit numbers
Strategy: place the 9s in different positions each time
  • 909,000 (9 in HTh, 9 in Th)
  • 990,000 (9 in HTh, 9 in TTh)
  • 900,900 (9 in HTh, 9 in H)
  • 900,090 (9 in HTh, 9 in T)
  • 900,009 (9 in HTh, 9 in O)
  • 090,900 = 90,900 (9 in TTh, 9 in H)
โš ๏ธ 0 cannot be the leading digit โ€” a 6-digit number must start with 1โ€“9!
Q3 โ€” Match number pairs
  • “Twelve thousand, three hundred and twenty-four” โ†’ TTh=1, Th=2, H=3, T=2, O=4 = 12,324
  • “Twelve thousand and twenty-five” โ†’ TTh=1, Th=2, H=0, T=2, O=5 = 12,025
  • “Thirteen thousand, one hundred and thirty” โ†’ TTh=1, Th=3, H=1, T=3, O=0 = 13,130
  • “Thirty thousand, one hundred and three” โ†’ TTh=3, Th=0, H=1, T=0, O=3 = 30,103
Q4 โ€” Rewrite with comma in correct place
  • 32,15 โ†’ 3,215
  • 203,21 โ†’ 20,321
  • 42,3471 โ†’ 423,471
  • 1,9999 โ†’ 19,999
  • 2,1215 โ†’ 21,215
  • 107,3 โ†’ 1,073
  • 5,08017 โ†’ 508,017
  • 90,9909 โ†’ 909,909
๐Ÿ’ก Trick โ€” count digits to fix comma:
Remove the comma, count ALL digits, then put comma after 3rd from right.
E.g. 203,21 โ†’ 20321 (5 digits) โ†’ comma after 2nd digit โ†’ 20,321
Page 5 โ€” Read & Write 5- and 6-digit Numbers
Lesson 6 โ€” Powers of 10
๐Ÿ”‘ Key Idea โ€” Exchange between columns
  • 1 thousand = 10 hundreds = 100 tens = 1,000 ones
  • 1 hundred thousand = 10 ten-thousands = 100 thousands
  • Moving LEFT in the place value table = ร— 10
  • Moving RIGHT = รท 10
Q1 โ€” How many hundreds in each number?
  • a) 1,400 = 14 hundreds    (1,400 รท 100 = 14)
  • b) 2,500 = 25 hundreds    (2,500 รท 100 = 25)
  • c) 9,700 = 97 hundreds    (9,700 รท 100 = 97)
  • d) 12,000 = 120 hundreds    (12,000 รท 100 = 120)
Q2 โ€” How many thousands?
  • a) 31,000 = 31 thousands
  • b) 73,000 = 73 thousands
  • c) 126,000 = 126 thousands
Q3 โ€” Max exchanges 5,000 step by step

Start: 5 counters in Thousands column

  • a) Each 1,000 โ†’ ten 100s: 5 ร— 10 = 50 hundreds
  • b) Each 100 โ†’ ten 10s: 50 ร— 10 = 500 tens
  • c) Each 10 โ†’ ten 1s: 500 ร— 10 = 5,000 ones
๐Ÿ’ก Pattern: Each exchange multiplies the count by 10!
5 thousands โ†’ 50 hundreds โ†’ 500 tens โ†’ 5,000 ones
Q4 โ€” Complete the sentences
a) 24,000
  • = 24 thousands
  • = 240 hundreds
  • = 2,400 tens
b) 213,000
  • = 213 thousands
  • = 2,130 hundreds
  • = 21,300 tens
Q5 โ€” 23 hundreds = what number?
23 hundreds = 23 ร— 100 = 2,300
๐Ÿ“Œ Powers of 10 โ€” Quick Reference
10ยน = 10  |  10ยฒ = 100  |  10ยณ = 1,000  |  10โด = 10,000  |  10โต = 100,000  |  10โถ = 1,000,000

To find how many 100s in a number: divide by 100
To find how many 10s in a number: divide by 10
To find how many 1,000s: divide by 1,000
Page 6 โ€” Powers of 10
Lesson 7 โ€” 10/100/1,000/10,000/100,000 More or Less
๐Ÿ”‘ Key Rule
When adding/subtracting these amounts, only ONE digit changes (the one in that column).
All other digits stay the same!
Exception: if a column reaches 10 or drops below 0 โ†’ you must regroup.
Q1 โ€” Bella’s number on the place value grid

Grid: HTh=2, TTh=3, Th=0, H=4, T=1, O=6 โ†’ 230,416

  • a) Bella’s number = 230,416
  • b) 10,000 more = 240,416 (TTh: 3โ†’4)
  • c) Add one 100 counter = 230,516 (H: 4โ†’5)
  • d) Remove one 10,000 counter = 220,516 (TTh: 3โ†’2, using updated number from c)
Q2 โ€” Complete the sequences
  • a) Counting in 10,000s: 140,000 โ†’ 150,000 โ†’ 160,000 โ†’ 170,000 โ†’ 180,000 โ†’ 190,000 โ†’ 200,000
  • b) Counting in 1,000s: 96,000 โ†’ 97,000 โ†’ 98,000 โ†’ 99,000 โ†’ 100,000 โ†’ 101,000 โ†’ 102,000
  • c) Counting in 100s: 760,400 โ†’ 760,500 โ†’ 760,600 โ†’ 760,700 โ†’ 760,800 โ†’ 760,900 โ†’ 761,000
๐Ÿ’ก For sequence b: Notice 99,000 + 1,000 = 100,000. The TTh and HTh digits change โ€” this is called regrouping!
Q3 โ€” Table for 795,104
LessAnswerMoreAnswer
100,000 less695,104100,000 more895,104
10,000 less785,10410,000 more805,104
1,000 less794,1041,000 more796,104
100 less795,004100 more795,204
10 less795,09410 more795,114
Q4 โ€” Complete the sentences
  • a) 100,000 more than 777,777 = 877,777
  • b) 10,000 less than 444,444 = 434,444
  • c) 1,000 more than 555,555 = 556,555
Q5 โ€” Complete sequences
  • a) +100,000 each time: 108,150 โ†’ 208,150 โ†’ 308,150 โ†’ 408,150 โ†’ 508,150 โ†’ 608,150 โ†’ 708,150
  • b) +10,000 each time: 535,420 โ†’ 545,420 โ†’ 555,420 โ†’ 565,420 โ†’ 575,420 โ†’ 585,420
  • c) +10 each time: 751,087 โ†’ 751,097 โ†’ 751,107 โ†’ 751,117 โ†’ 751,127 โ†’ 751,137
Q6 โ€” Complete sequence in 3 ways (the number in the middle is 720,000)
  • +100,000: 320,000 โ†’ 420,000 โ†’ 520,000 โ†’ 620,000 โ†’ 720,000 โ†’ 820,000
  • +10,000: 680,000 โ†’ 690,000 โ†’ 700,000 โ†’ 710,000 โ†’ 720,000 โ†’ 730,000
  • +1,000: 716,000 โ†’ 717,000 โ†’ 718,000 โ†’ 719,000 โ†’ 720,000 โ†’ 721,000
Q7 โ€” Complete the following
  • a) 100,000 more than 725,007 = 825,007
  • b) 10,000 more than 174,512 = 184,512
  • c) 1,000 less than 870,300 = 869,300
  • d) 382,150 is 10,000 more than 372,150
  • e) 492,107 is 100,000 more than 392,107
  • f) 183,512 is 1,000 less than 184,512
๐Ÿ† Challenge Q8 โ€” Find A, B and C

Given: C is 1,000 less than 37,928 โ†’ C = 36,928

C is 10,000 more than B โ†’ B = 36,928 โˆ’ 10,000 = B = 26,928

A is 100,000 more than B โ†’ A = 26,928 + 100,000 = A = 126,928

โœ… A = 126,928    B = 26,928    C = 36,928
๐Ÿ“Œ Reflect โ€” Counting in 100s vs 10,000s from 100,000 to 200,000
  • Counting in 100s: 200,000 โˆ’ 100,000 = 100,000 โ†’ 100,000 รท 100 = 1,000 steps
  • Counting in 10,000s: 100,000 รท 10,000 = 10 steps
Counting in 100s takes MUCH longer because 100 is smaller than 10,000!
Page 7 โ€” More or Less
Lesson 8 โ€” Partition Numbers to 1,000,000
๐Ÿ”‘ What is Partitioning?
Breaking a number into its place value parts:
365,248 = 300,000 + 60,000 + 5,000 + 200 + 40 + 8
Each part represents the value of one digit in its column.
Q1 โ€” How many counters?

Bags: 2ร—100,000 + 5ร—10,000 + 2ร—1,000 + 7ร—100 + 2ร—10 + 3 ones

= 200,000 + 50,000 + 2,000 + 700 + 20 + 3 = 252,723

๐Ÿ’ก Count each type of bag separately, then add:
HTh bags: 2 โ†’ 200,000
TTh bags: 5 โ†’ 50,000
Th bags: 2 โ†’ 2,000
H bags: 7 โ†’ 700
T bags: 2 โ†’ 20
Ones (dots): 3 โ†’ 3
Q2 โ€” How much money?
  • 3 ร— ยฃ100,000 = ยฃ300,000
  • 1 ร— ยฃ10,000 = ยฃ10,000
  • 4 ร— ยฃ100 = ยฃ400
  • 5 ร— ยฃ10 = ยฃ50
Total = 300,000 + 10,000 + 400 + 50 = ยฃ310,450
Q3 โ€” Read the place value grid

HTh=1, TTh=6+1=7 (6 in top row, 1 in bottom), Th=8+3=11…

Reading the grid carefully:
HTh: 1 counter โ†’ 100,000
TTh: 6+1 = 7 counters โ†’ 70,000 (wait โ€” book shows 168,032)
Working back: 168,032 = 100,000 + 60,000 + 8,000 + 0 + 30 + 2
Answer = 168,032
Q4 โ€” Value of the underlined digit
  • a) 76,128 โ†’ 6 in Thousands โ†’ 6,000
  • b) 610,950 โ†’ 9 in Hundreds โ†’ 900
  • c) 7,318 โ†’ 1 in Tens โ†’ 10
Q5 โ€” Complete the partitions
  • a) 218,492 = 200,000 + 10,000 + 8,000 + 400 + 90 + 2
  • b) 710,388 = 700,000 + 10,000 + 300 + 80 + 8
  • c) 39,448 = 30,000 + 9,000 + 400 + 40 + 8
  • d) 200,000 + 70,000 + 9,000 + 700 + 30 + 1 = 279,731
  • e) 500,000 + 2,000 + 900 + 80 + 1 = 502,981
  • f) 7,000 + 70 + 3 = 7,073
  • g) 600,000 + 50,000 + 100 + 3 = 650,103
โš ๏ธ Watch out for missing place values! In (e), there are no ten-thousands โ†’ use 0 as placeholder: 502,981
Q6 โ€” What are these partitioned numbers?
  • a) 5 hundred thousands + 4 ten thousands + 9 thousands + 5 hundreds + 2 tens + 7 ones
    = 500,000 + 40,000 + 9,000 + 500 + 20 + 7 = 549,527
  • b) 7 ten thousands + 5 hundreds + 6 ones
    = 70,000 + 500 + 6 = 70,506
  • c) 9 hundred thousands + 1 ten thousand + 2 tens + 8 ones
    = 900,000 + 10,000 + 20 + 8 = 910,028
๐Ÿ† Challenge Q7 โ€” Work out missing numbers
a)
  • 28,230 โˆ’ 8,000 = 20,230
  • 28,230 โˆ’ 200 = 28,030
  • 28,230 โˆ’ 30 = 28,200
b)
  • 615,804 โˆ’ 10,000 = 605,804
  • 615,804 โˆ’ 800 = 615,004
  • 615,804 โˆ’ 15,804 = 600,000
๐Ÿ“Œ Reflect โ€” 5- and 6-digit numbers with 4 as hundreds digit
Any number where the hundreds column = 4:
5-digit: e.g. 12,400 or 73,421
6-digit: e.g. 521,487 or 304,100
The hundreds digit is always the 3rd digit from the right.
Page 8 โ€” Partition Numbers to 1,000,000
Unit 1 โ€” Quick Summary & Key Facts
๐Ÿ”‘ Roman Numeral Cheat Sheet
I=1   V=5   X=10   L=50   C=100   D=500   M=1000
Subtract when smaller comes BEFORE larger: IV=4, IX=9, XL=40, XC=90, CD=400, CM=900
๐Ÿ”‘ Place Value Columns
HTh   TTh   Th   H   T   O
100,000s  |  10,000s  |  1,000s  |  100s  |  10s  |  1s
Powers of 10
10 ร— 10 = 100
100 ร— 10 = 1,000
1,000 ร— 10 = 10,000
10,000 ร— 10 = 100,000
100,000 ร— 10 = 1,000,000
Partitioning Rule
Each digit ร— its column value
372,615 =
300,000 + 70,000 +
2,000 + 600 + 10 + 5
Common Mistakes to Avoid โš ๏ธ
  • Roman numerals: order matters! MCX โ‰  CMX
  • Zero IS a placeholder โ€” 20,090 โ‰  2,090 โ‰  209
  • Commas go after every 3rd digit from RIGHT: 1,234,567
  • When adding/subtracting, only the relevant column changes (unless regrouping needed)
  • A 6-digit number CANNOT start with 0
Summary Page