HS-IP-G4A-MATHS-LESSON 3.6

Multiply mentally to find the product

(8 x 350)=(4 x ___) x 350

Multiply mentally to find the product

7 x 402= 7 x ( ___ + 2)

Multiply mentally to find the product:

302 x 7

Multiply mentally to find the product:

6 x 320

Multiply mentally to find the product:

2 x 298 =

Multiply mentally to find the product:

8 x 58 =

Each zebra at a zoo eats 100 pounds of hay and 2 pounds of fruits and vegetables every day. How many pounds of food does the zoo need to feed 1 zebra for 1​ week? Use mental math to solve.

Tim has a stamp collection. On Monday, he got 17 new stamps. On Tuesday, he gave 7 stamps to his friends. After giving away the stamps, Tim had 138 stamps left in his collection. How many stamps did Tim have to start with.

Isabelle used compensation to find the product of 6 x 502. First, she found 6 x 500 = 3,000. Then she adjusted the product by subtracting 6 groups of 2 to get her final answer of 2,988. Explain Isabelle's mistake and find the correct answer.

Choose the correct answer below.

• A. Isabelle should have added 6 groups of 2 to 3,000 instead of subtracting. The correct answer is 3,012.

• B. Isabelle should have subtracted 6 groups of 2 from 3,000. The correct answer is 2,978.

• C. Isabelle should have added 2 groups of 6 to 3,000 instead of subtracting. The correct answer is 3,022.

• D. Isabelle should have subtracted 2 groups of 6 from 3,000. The correct answer is 2,998.

Which of the following expressions shows how to use mental math to find the product of 7 x 56?

• A. 7x5 x6

• B. (7x50)+(7x6)

• C. (7x55)+(7x11)

• D. (7 x60) - (7 x4)

• E. 7x(50x6)