Mental Multiplication
Standard Algorithm
Estimate!
Random
100

300 x 5

1,500
100

7,693 x 3

23,079

100

Estimate 6,291 x 5 by rounding 6,291 to the nearest thousand.

6,000 x 5 = 30,000

100
1,234 x 67

82,678

200
400 x 40

16,000

200

534 x 39

20,826

200

Estimate 492 x 53 by rounding 492 to the nearest hundred and rounding 53 to the nearest ten.

500 x 50 = 25,000

200

Find the number that is equal to 42,395 x 3 without calculating the exact product.

a) 127,185 

b) 27,185

c) 1,200,200

d) 128,290

a) 127,185

300

21,000 x 3

63,000

300

676 x 76

51,376

300

Mariam estimated the product of 9,294 x 6 to be 54,000. What number did she round 9,294 to?

Mariam rounded 9,294 to 9,000.

9,000 x 6 = 54,000

300

Use estimation to find which problem is greater.

a) 28 x 671

b) 51 x 32

A is greater.
400

5 x 299

1,495

400

3,842 x 28

107,576

400

Manos estimated the product of 9,294 x 6 to be 55,800. What number did he round 9,294 to?

Manos rounded 9,294 to 9,300.

9,300 x 6 = 54,000 + 1,800 = 55,800

400

A special Dubai chocolate bar costs $159. A rare Labubu costs 4 times as much as the chocolate bar. Ms. Saba bought 2 chocolate bars and a rare Labubu. How much did she pay in total for the chocolate bars and the Labubu? Write your answer in a sentence and label units.

Ms. Saba spent $954 on the chocolate bars and the Labubu (but she probably should have saved her money instead).

500

4 x 360

1,440

500

One waffle machine costs $371. How much do 8 machines cost? Write your answer in a sentence.

Eight machines cost $2,968.

500

Mica and George both estimated the product of 2,190 x 5. 

Mica rounded 2,190 to 2,000. George rounded 2,190 to 2,200. 

Whose estimate will be closer to the actual answer?

George's estimate will be closer because his rounded number is closer to the original number. 

500

A zoo receives 1,143 adult visitors and 2,817 child visitors daily. How many visitors will the zoo receive in 12 days? Write your answer in a sentence and label units.

The zoo will receive 47,520 visitors in 12 days.

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