EnVision Topic 7 Fourth Grade

Using Mental Math

100

The basic fact in 700 x 30

What is 7 x 3

200

The number of zeroes in the answer to the problem 600 x 50.

What is four

300

400 x 50

What is 20,000

400

200 x 800

What is 160,000

500

How can you use mental math to solve 40,000 x 500?

What is multiplying the basic fact 4 x 5, then adding the 6 zeroes from both factors into the product. The product is 20,000,000

Esimating Products

100

Estimate. 12 x 89

What is 900?

200

Estimate. 27 x 41

What is 1,200?

300

Estimate. 46 x 18

What is 1,000?

400

Estimate. 43 x 67

2,800

500

Using estimation, find the problem below with the greatest product: 39 x 21 or 32 x 32 and how you know.

What is 32 x 32 because 32 rounds to 30, so 30 x 30=900 while 39 rounds to 40 and 21 rounds to 20, so 20 x 20=800

Multiplying 2 Digit by 2 Digit Numbers

100

65 x 30

What is 1,950

200

80 x 89 

What is 7,120

300

70 x 68 

What is 4,760?

400

93 x 50

4,650

500

70 x 47

What is 3,290?

Arrays/Expanded Algorithms

100

Teacher - Open Topic 7 Review array 1.

Write a multiplication problem to find the shaded area.

What is 6 x 30?

200

Teacher - Open Topic 7 Review array 2.

Write a multiplication problem to find the shaded area.

What is 20 x 30?

300

Teacher - Open Topic 7 Review array 3.

Write a multiplication problem to find the total number of squares.

What is 24 x 30?

400

Teacher - Open Topic 7 Review array 4.

Write a multiplication problem to find the shaded area.

What is 20 x 30?

500

81 x 46.

What is 3,720?

Two Question Problems

100

 Susan walked 3 miles and Maxine walked 2 miles to raise funds for Skinner School's Walk-a-Thon. A parent donated $50 for every mile they walked. How much did the parent donate?

What is $250?

200

Ben has 4 rare baseball cards and Emmett has 3. They sold their cards for $10 each. How much money did they make in all?

What is $70?

300

Sophia and Mila were making friendship bracelets. They used 4 pink ribbons, 3 blue ribbons, and 2 red ribbons for each one. How many ribbons did they use after Mila and Sophia made 20 bracelets?

What is, 180 ribbons?

400

Alex E. buys lunch at Subway. His sandwich costs $4, his chips were $2, and his drink was $1. If he bought lunch at subway once a week for 2 months, how much would he have spent at the end of the two months?

What is $56?

500

Jeanette gets paid $5 an hour for babysitting. Grace gets paid 3 times as much as Jeanette. How much more does Grace get paid than Jeanette?

What is $10 more.