Multiply 3-digit numbers by 2-digit numbers using the standard algorithm
Understand and apply properties of multiplication (commutative, associative, distributive, identity, zero)
Multiply numbers by 10, 100, and 1000 using shortcut rules
Estimate products by rounding numbers before multiplying
Handle multiplication with zeros in the middle (e.g., 305 Γ 42)
Solve real-life word problems involving multiplication in Indian contexts
Extend multiplication skills to 4-digit Γ 2-digit numbers
Introduction β Multiplication in Daily Life
In Class 4, you learned to multiply 2-digit numbers by 2-digit numbers. Now in Class 5, we take it further β you will learn to multiply 3-digit numbers by 2-digit numbers and even begin working with 4-digit numbers!
Think about these real-life situations:
A school orders 48 boxes of notebooks, and each box has 125 notebooks. How many notebooks in total? (125 Γ 48)
A train travels 345 km every day. How far does it travel in 28 days? (345 Γ 28)
Arjun's father buys 36 bags of rice at βΉ750 per bag. What is the total cost? (750 Γ 36)
A farmer plants 64 rows of mango saplings with 215 saplings in each row. How many saplings in all? (215 Γ 64)
All of these need 3-digit Γ 2-digit multiplication. Let us learn how to do it step by step!
Quick Revision β What You Already Know
Before we begin, let us quickly revise what multiplication means and some facts you already know:
What is Multiplication?
Multiplication is repeated addition. For example: 5 Γ 3 = 5 + 5 + 5 = 15
The numbers being multiplied are called factors. The answer is called the product.
In 345 Γ 23 = 7,935 β 345 and 23 are factors; 7,935 is the product.
The larger number is usually called the multiplicand and the smaller one the multiplier.
Multiplication Tables β Quick Check
You must know your tables from 2 to 12 by heart. Here is a quick check:
Γ
6
7
8
9
12
7
42
49
56
63
84
8
48
56
64
72
96
9
54
63
72
81
108
12
72
84
96
108
144
Think About It: Why do we need tables? Because every big multiplication problem breaks down into smaller multiplications from the tables! When we multiply 345 Γ 23, we actually use tables of 3, 2, and single-digit multiplication many times.
Multiplying by 10, 100, and 1000
Before we learn long multiplication, here is a powerful shortcut that makes many calculations easy:
The Zero Rule
Multiply by 10: Add one zero at the end of the number.
Multiply by 100: Add two zeros at the end of the number.
Multiply by 1000: Add three zeros at the end of the number.
Examples:
Multiplication
Result
How?
346 Γ 10
3,460
Write 346, add one zero β 3460
346 Γ 100
34,600
Write 346, add two zeros β 34600
346 Γ 1000
3,46,000
Write 346, add three zeros β 346000
250 Γ 10
2,500
Write 250, add one zero β 2500
250 Γ 100
25,000
Write 250, add two zeros β 25000
480 Γ 1000
4,80,000
Write 480, add three zeros β 480000
Multiplying by Multiples of 10 (20, 30, 40...)
To multiply by 20, 30, 40, etc., first multiply by the non-zero digit, then add the zero(s):
Examples: 345 Γ 20: First, 345 Γ 2 = 690. Then add one zero β 6,900 250 Γ 60: First, 250 Γ 6 = 1,500. Then add one zero β 15,000 178 Γ 300: First, 178 Γ 3 = 534. Then add two zeros β 53,400 465 Γ 40: First, 465 Γ 4 = 1,860. Then add one zero β 18,600
Image needed: A visual showing the pattern of multiplying by 10, 100, 1000. Show a number (e.g., 345) with zeros being added at the end step by step. Use arrows and colour-coded zeros (green for Γ10, blue for Γ100, red for Γ1000). Style: Clean diagram, colourful arrows, child-friendly, step-by-step visual Size: 700Γ350px
Standard Algorithm β Long Multiplication (3-Digit Γ 2-Digit)
The standard algorithm (also called long multiplication or column method) breaks the multiplication into simple steps. Here is how it works:
Steps for 3-Digit Γ 2-Digit Multiplication
Step 1: Write the 3-digit number (multiplicand) on top and the 2-digit number (multiplier) below it, aligned to the right.
Step 2: Multiply the multiplicand by the ones digit of the multiplier. Write this as the first partial product.
Step 3: Write a zero placeholder in the ones place of the next line. Then multiply the multiplicand by the tens digit of the multiplier. Write this as the second partial product.
Step 4:Add both partial products to get the final answer (product).
Step 2: 345 Γ 2 = 690, but since 2 is in the tens place, write it as 6,900 (add a zero)
β 5Γ2=10, write 0 carry 1. 4Γ2=8, +1=9. 3Γ2=6.
Second partial product = 6,900
Step 3: Add: 1,035 + 6,900 = 7,935
Therefore, 345 Γ 23 = 7,935
Image needed: A clear step-by-step long multiplication visual showing 345 Γ 23. Show the column layout with the multiplicand on top, multiplier below, partial products clearly labelled with arrows showing "multiply by ones" and "multiply by tens (shift left)". Final addition shown with carrying marks. Style: Clean diagram on grid paper background, colour-coded steps (blue for first partial product, green for second), child-friendly Size: 600Γ500px
Think About It: Notice that when we multiply a 3-digit number by a 2-digit number, the answer can be a 4-digit or 5-digit number. When we multiply a 4-digit number by a 2-digit number, the answer can be a 5-digit or 6-digit number! Can you figure out why?
Properties of Multiplication
Multiplication has some special properties (rules) that always work, no matter what numbers you use. These properties make calculations easier and help us check our answers.
Property
Rule
Example
Commutative Property (Order Property)
a Γ b = b Γ a Changing the order of factors does not change the product.
a Γ 1 = a Any number multiplied by 1 stays the same.
567 Γ 1 = 567 9,999 Γ 1 = 9,999
Zero Property
a Γ 0 = 0 Any number multiplied by 0 equals 0.
345 Γ 0 = 0 99,999 Γ 0 = 0
Image needed: A visual showing the Distributive Property of multiplication. Show 345 Γ 23 being broken into 345 Γ 20 + 345 Γ 3, with rectangular area models. One large rectangle split into two smaller rectangles showing how the areas add up to the total product. Style: Area model diagram, colour-coded sections (blue and green), labels with numbers, child-friendly Size: 700Γ400px
Using the Distributive Property to Multiply Mentally:
Estimation means finding an approximate answer quickly by rounding numbers before multiplying. This is useful to:
Check if your answer is reasonable (not too big or too small)
Get a quick rough answer when an exact answer is not needed
Spot mistakes in your calculation
How to Estimate a Product
Step 1: Round each factor to the nearest ten, hundred, or leading digit.
Step 2: Multiply the rounded numbers.
The estimated product will be close to the actual product.
Examples:
Actual Problem
Round to
Estimated Product
Actual Product
489 Γ 52
500 Γ 50
25,000
25,428
312 Γ 48
300 Γ 50
15,000
14,976
678 Γ 23
700 Γ 20
14,000
15,594
195 Γ 41
200 Γ 40
8,000
7,995
845 Γ 67
850 Γ 70
59,500
56,615
Think About It: Meena calculated 345 Γ 23 and got 79,350. Can she use estimation to check? Round: 350 Γ 20 = 7,000. Her answer of 79,350 is about 10 times too big! She probably made a mistake. (The correct answer is 7,935.)
Multiplication with Zero in the Middle
When a number has a zero in the middle (like 305, 700, 408), the multiplication works the same way β just remember that any digit multiplied by 0 gives 0.
Problem 4: Arjun's father buys 52 bags of wheat at βΉ485 per bag for their ration shop. What is the total cost?
Solution: Total cost = βΉ485 Γ 52
485 Γ 2 = 970 | 485 Γ 5 = 2,425 β 24,250 | 970 + 24,250 = 25,220 Answer: The total cost is βΉ25,220.
Problem 5: A school has 38 classrooms. Each classroom has 45 desks. The school wants to buy new chairs at βΉ375 per chair (one chair per desk). What is the total cost of chairs?
Solution:
Step 1: Total chairs needed = 38 Γ 45 = 1,710
Step 2: Total cost = 1,710 Γ 375
This is a bigger multiplication! Let us use the distributive property:
1,710 Γ 375 = 1,710 Γ (400 β 25) = 6,84,000 β 42,750 = βΉ6,41,250 Answer: The total cost of chairs is βΉ6,41,250.
Image needed: A colourful illustration of an Indian market/shop scene showing: bags of rice/wheat with price tags (βΉ485), crates of mangoes, boxes of school supplies. A shopkeeper with a calculator. Numbers and multiplication symbols visible to show the math connection to real life. Style: Warm, colourful cartoon illustration, Indian setting, child-friendly characters Size: 750Γ450px
Key Words
Term
Meaning
Multiplicand
The number being multiplied (the larger number, written on top)
Multiplier
The number you multiply by (the smaller number, written below)
Product
The answer you get after multiplying
Factors
Numbers that are multiplied together to give a product
Partial Product
The result of multiplying by one digit of the multiplier (an intermediate step)
Estimate
An approximate answer found by rounding before calculating
Commutative
Order does not matter: a Γ b = b Γ a
Associative
Grouping does not matter: (aΓb)Γc = aΓ(bΓc)
Distributive
Break apart: aΓ(b+c) = aΓb + aΓc
Identity (Γ1)
Any number Γ 1 = the same number
Zero Property
Any number Γ 0 = 0
Key Points to Remember
To multiply a 3-digit number by a 2-digit number: multiply by ones digit, then by tens digit (with a zero placeholder), then add both partial products.
Multiplying by 10: add one zero. By 100: add two zeros. By 1000: add three zeros.
For multiples of 10 (20, 30, 40...): multiply by the non-zero digit first, then add the zero(s).
Use estimation (rounding) to quickly check if your answer is reasonable.
The distributive property lets you break hard multiplications into easier parts.
The commutative property means you can swap the order: 345 Γ 23 = 23 Γ 345.
When there is a zero in the middle of a number, multiply normally β 0 times anything is 0.
A 3-digit Γ 2-digit product can be 4 digits (100Γ10=1,000) or 5 digits (999Γ99=98,901).
Always carry over when a single-digit multiplication gives a 2-digit result.
Check word problems: identify which numbers to multiply, solve, and write the answer with correct units.
Finished learning? Now test what you know!
π― Quick Quiz β Test Yourself!
Answer these questions right here. You get instant feedback β no paper needed!
Score: 0 / 8
1. 345 Γ 10 = ?
Multiplying by 10 adds one zero: 3,450.
2. 25 Γ 16 = ?
25 Γ 16 = 25 Γ 4 Γ 4 = 100 Γ 4 = 400.
3. Any number multiplied by 0 gives:
Zero property: any number Γ 0 = 0.
4. 123 Γ 45 is closest to which estimate?
120 Γ 45 β 5,400, closest to 5,000. (Exact: 5,535.)
4. The product of two 2-digit numbers is always a 4-digit number.
5. Estimation gives us the exact answer.
G. Choose the correct answer (MCQ):
1. What is 345 Γ 20?
a) 690b) 6,900c) 69,000d) 3,450
2. Which property says a Γ b = b Γ a?
a) Associativeb) Distributivec) Commutatived) Identity
3. The estimated product of 489 Γ 52 (rounding to nearest tens) is approximately:
a) 20,000b) 25,000c) 30,000d) 2,500
4. What is the second partial product when multiplying 567 Γ 48?
a) 4,536b) 2,268c) 22,680d) 27,216
H. Word Problems:
1. Ravi's school library has 48 shelves. Each shelf holds 175 books. How many books are in the library?
2. A train ticket from Delhi to Jaipur costs βΉ345. If 56 passengers buy tickets, how much money does the railway collect?
3. Sita's mother buys 24 packets of biscuits for a school picnic. Each packet costs βΉ125. What is the total cost?
4. A farmer has 72 rows of coconut trees. Each row has 135 trees. How many coconut trees does the farmer have?
5. An auto-rickshaw travels 185 km every day. How many kilometres does it travel in 31 days?
6. Meena's father orders 65 cartons of mangoes for his shop. Each carton weighs 12 kg and costs βΉ480. Find: (a) the total weight of all cartons, and (b) the total cost.
Activity β Shopping Bill Calculator
Imagine you are helping at a stationery shop. A school has placed a bulk order. Calculate the total bill:
Item
Quantity
Price per Item (βΉ)
Total Cost (βΉ)
Notebooks (single line)
48
βΉ65
Pencil boxes
36
βΉ125
Geometry boxes
24
βΉ185
Erasers (packets)
15
βΉ240
Drawing sheets (bundles)
12
βΉ350
Grand Total:
Challenge: First estimate the grand total by rounding each price to the nearest hundred. Then calculate the exact total. How close was your estimate?
Want to review the lesson again?
Mathematics
Multiplication β 3-Digit Γ 2-Digit
Class 5 | CBSE / NCERT / ICSE
Name: Class: Date:
Learning Objectives
Multiply 3-digit numbers by 2-digit numbers using the standard algorithm
Understand properties of multiplication (commutative, associative, distributive)
Multiply by 10, 100, and 1000 using shortcut rules
Estimate products by rounding
Solve real-life word problems involving multiplication
Introduction
In Class 4, you multiplied 2-digit Γ 2-digit numbers. Now in Class 5, we extend to 3-digit Γ 2-digit multiplication. Real-life examples: buying 48 boxes of 125 notebooks (125Γ48), a train travelling 345 km/day for 28 days (345Γ28), buying 36 bags of rice at βΉ750 each (750Γ36).
Quick Revision
What is Multiplication? Repeated addition. 5Γ3 = 5+5+5 = 15. Vocabulary: Multiplicand Γ Multiplier = Product. Both are called Factors.
Γ
6
7
8
9
12
7
42
49
56
63
84
8
48
56
64
72
96
9
54
63
72
81
108
12
72
84
96
108
144
Multiplying by 10, 100, 1000
Γ10: Add one zero | Γ100: Add two zeros | Γ1000: Add three zeros Multiples of 10: Multiply by non-zero digit first, then add the zero(s).
Problem
Result
Problem
Result
346 Γ 10
3,460
345 Γ 20
6,900
346 Γ 100
34,600
250 Γ 60
15,000
346 Γ 1000
3,46,000
178 Γ 300
53,400
[Image: Visual showing pattern of multiplying by 10/100/1000 β zeros being added with colour-coded arrows]
Standard Algorithm β Long Multiplication
Steps:
1. Multiply multiplicand by ones digit of multiplier β First partial product
2. Write zero placeholder, multiply by tens digit β Second partial product
3. Add both partial products β Final product
How to estimate: Round each factor β Multiply the rounded numbers β Get approximate answer.
Problem
Rounded
Estimate
Actual
489 Γ 52
500 Γ 50
25,000
25,428
312 Γ 48
300 Γ 50
15,000
14,976
678 Γ 23
700 Γ 20
14,000
15,594
195 Γ 41
200 Γ 40
8,000
7,995
Tip: Use estimation to check your answer! If your calculation gives 79,350 for 345Γ23, estimate: 350Γ20 = 7,000. Your answer is 10Γ too big β check again!