Grade 4 - Progress in Mathematics

Multiply by

the ones.

Multiply by

the tens.

Add the

partial products.

Multiply by Two-Digit Numbers

4-12

James baked 24 dozen crescent

rolls. How many rolls did James bake?

To find how many rolls,

multiply: 24 
 12

First, use rounding 24 
 12

to estimate:

20 
 10  200

Then multiply.

Here is one way to multiply 24 
12.

12 12 12 12


 24 
 4 
 20 
 24

48  240  288

Here is another way to multiply 24 
12.

12 12 12


 24 
 24 
 24

48 48 48

240  240

288

James baked 288 crescent rolls.

Think

24  20  4

Think

1 dozen  12

Think

288 is close to 200.

The answer is reasonable.

4 
 12 20 
 12

partial

products

3.3

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