Multiplying Two- and Three- Digit

Numbers by a One- Digit Number

Step 1

Think about 3 groups of 24.

243x

243x

Step 2

Multiply the ones.

Think:4 x 3 = 12

243x

Step 3

Regroup 12 ones as 1 ten and 2 ones. Write down the ones. Carry the tens.

243x2

1

Step 4

Then multiply the bottom ones times the tens. Add in the one ten you carried over.

Think:6 tens + 1 ten = 7 tens

7

243x2

1

Step 5

Your final answer is 72.

7

243x2

1

Let’s try another problem!

Step 1

Think about 5 groups of 45.

455x

455x

Step 2

Multiply the ones.

Think:5 x 5 = 25

455x

Step 3

Regroup 25 ones as 2 tens and 5 ones. Write down the ones. Carry the tens.

455x5

2

Step 4

Then multiply the bottom ones times the tens. Add in the two ten you carried over.

Think:20 tens + 2 tens = 22

455x5

2

22

Step 5

Your final answer is 225.

Let’s try a harder problem!

455x5

2

22

Step 1

Think about 4 groups of 364.

644x

3

Step 2

Multiply the ones.

Think:4 x 4 = 16

644x

3644x

3

Step 3

Regroup 16 ones as 1 ten and 6 ones. Write down the ones. Carry the tens.

6

1

644x

3

Step 4

Then multiply the bottom ones times the tens. Add in the one ten you carried over.

Think:24 tens + 1 ten = 25 tens

6

644x

31

Step 5

Regroup 25 tens as two hundreds and five tens. Write down the tens. Carry the hundreds.

644x

3

6

1

5

2

Step 6

Then multiply the bottom ones times the hundreds. Add in the two hundreds you carried over.

Think:12 hundreds + 2 hundreds = 14

6

644x

312

5

Step 7

Your final answer is 1,456. 6

644x

312

51,4

Now try some on your own!