Lesson 12.1

Multiplying 2-digit Numbers

Mr. Henson grows tomatoes. There are 35 plants on each tray. Mr. Henson has 88 trays. How many tomato plants does he have in all?

Step 1: Think of 35 as 3 tens and 5 ones.

Multiply 88 x the 5 ones.

5 x 88

Step 1: Think of 35 as 3 tens and 5 ones.

Multiply 88 x the 5 ones.

5 x 88

H T O

x

483

85

4 4 0

Mr. Henson grows tomatoes. There are 35 plants on each tray. Mr. Henson has 88 trays. How many tomato plants does he have in all?

Step 2: Multiply 88 by the 3 tens (30)

Place a zero

30 x 88

Step 2: Multiply 88 by the 3 tens (30)

Place a zero

30 x 88

T H T O

x

2483

85

4 4 0

2 6 4 0

Mr. Henson grows tomatoes. There are 35 plants on each tray. Mr. Henson has 88 trays. How many tomato plants does he have in all?

Step 3

Add the products

Step 3

Add the products

Th H T O

8 8

x 3 5

4 4 0

+ 2 6 4 03, 0 8 0

PracticeH T O

2 9

x 3 8

Th H T O272 9

x 3 8

2 3 2

+ 8 7 01, 1 0 2

PracticeH T O

$5 5

x 6 2

Th H T O31

$5 5

x 6 2

1 1 0

+ 3 3 0 0 $3 , 4 1 0

Hints

When you multiply 2-digit numbers, start by multiplying the ones in the number below.

When multiplying the tens, don’t forget to use a zero to mark its place value.

Don’t forget to add numbers that are traded and cross the numbers out when you’ve finished adding them.

When you multiply 2-digit numbers, start by multiplying the ones in the number below.

When multiplying the tens, don’t forget to use a zero to mark its place value.

Don’t forget to add numbers that are traded and cross the numbers out when you’ve finished adding them.

Try TheseH T O

3 7

x 2 2

H T O

5 4

x 3 1

H T O

4 2

x 2 6

How is multiplying a 2-digit number like multiplying a 1-digit number?You need to know basic facts.

You need to understand regrouping.

You need to know basic facts.

You need to understand regrouping.