Name:________________________
Block:___________________________
2.5
Estimating Products
OBJECTIVE: To use rounding and multiplication patterns to estimate products.
Vocabulary:
Product: The answer to a multiplication problem.
Estimating is commonly used to find quick answers in situations where the answer does not need to be
exact. Estimating is very helpful for times that you must use mental math. In this lesson we will use a
combination of two skills that we have already covered in class. Those skills are rounding and using
multiplication patterns.
Example: Estimate the product.
3,457 x 268
Step 1: Rounding
In order to complete our estimation using mental math we need to round each number. Our goal is to
round the number so that we have one digit followed by zeros. Here is what it will look like:
3,457 x 268
3,000 x 300
Step 2: Using patterns
Now that we have rounded, we can use our multiplication patterns with zero to finish our estimation.
Reminder: When we use patterns, we multiply the basic facts and then add on the zero.
3,000 x 300
3x3=9
Then add on the five zeros: 900,000
Our estimation is: about 900,000
Estimate the product:
1.) 65 x 22
2.) 54 x 419
3.) 33 x 180
4.) 91 x 43
5.) 88 x 27
6.) 5,720 x 79
Name:________________________
Block:___________________________
2.5
Estimate the sum:
1.) 91 x 49
2.) 195 x 23
3.) 894 x 605
4.) 641 x 31
5.) 555 x 470
6.) 4,096 x 12
7.) 42 x 1,912
8.) 4 x 96, 725
9.) 456 x 76
10.) 26 x 725
11.) 44 x 260
12.) 38 x 4,118
Mr. Hoppe has been saving money up for a new couch. If Mr. Hoppe saves $20 each week for 40 weeks,
how much does the couch cost? (Hint: Use multiplication patterns!!!)
Mrs. Ewald has been saving $36 dollars each week to go on a vacation to Alaska. She has determined
that it will take her 94 weeks to save enough money for the trip. Use rounding and multiplication
patterns to estimate the total cost of the vacation.