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Quick Check
Complete the following grid for building tables 11 to 20.

× 1 2 3 4 5 6 7 8 9 10
11
12 48
13
14
15
16

17
18 126
19
20

Multiplication by 1-Digit nuMber (Without regrouping)

Multiplication of a 2-digit number by a 1-digit number

We have already learned the multiplication of a 2-digit number by 1 digit. Let us revise.
Example: Multiply 12 by 3.

Solution: Step 1: Multiply the ones. Step 2: Multiply the tens.

2 ones × 3 = 6 ones 1 ten × 3 = 3 tens
t O t O

1 2 1 2 Knowledge Desk
× 3 × 3 When multiplying an even
number by 6, the product
6 3 6 ends in the same even digit.
Thus, 12 × 3 = 36 For example, 6 x 2 = 12,
6 x 4 = 24, 6 x 6 = 36, etc.

Multiplication of a 3-digit number by a 1-digit number

For preparation of International Mathematics Olympiad (IMO), a teacher gave 3 booklets
to each student.

Ravi: There are 103 questions in each booklet.

Rupa: Okay, then how many questions are there in all the 3 booklets?
Ravi: We need to multiply 103 by 3 to know the total number of
questions in all.

Rupa: Let us arrange the numbers in columns and multiply them step by step.

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