Prep · Decimal multiplication, fraction area, expressions

1. 1.

   Find 2.4 × 5.

   Answer. 12

   2.4 × 5 = 12.

2. 2.

   Compute 78 × 24. Write the product in simplest form.

   Answer. 716

   78 × 24 = 1432 = 716.

3. 3.

   Evaluate 8 + 3 × 4.

   Answer. 20

   Multiply first: 3 × 4 = 12. Then 8 + 12 = 20.

4. 4.

   Find the area of a rectangle with length 34 m and width 3 m.

   Answer. 214 square m

   A = ℓ × w = 34 × 3 = 214 square m.

5. 5.

   Find 1.8 × 5. Then Malik needs 5 of that amount. What is the total they need?

   Answer. 45

   1.8 × 5 = 9. Then multiply by 5: 45.

6. 6.

   A pan is 15 full of brownies. Grace eats 12 of what is in the pan. How much of a whole pan did Grace eat?

   Answer. 110

   15 of a pan, then 12 of that: 15 × 12 = 110.

7. 7.

   Evaluate 4 + 5 × 6. Then Owen needs 3 of that amount. What is the total they need?

   Answer. 102

   Multiply first: 5 × 6 = 30. Then 4 + 30 = 34. Then multiply by 3: 102.

8. 8.

   Grace is covering 3 identical bulletin boards. Each is 45 cm by 2 cm. What total area must be covered?

   Answer. 445 square cm

   One area is 135. 3 of them: 135 × 3 = 445 square cm.

9. 9.

   Find 3.7 × 6. Then Priya needs 3 of that amount. What is the total they need?

   Answer. 66.6

   3.7 × 6 = 22.2. Then multiply by 3: 66.6.

10. 10.

    A pan is 12 full of brownies. Jonah eats 25 of what is in the pan. How much of a whole pan did Jonah eat?

    Answer. 15

    12 of a pan, then 25 of that: 12 × 25 = 15.

11. 11.

    Think

    Priya tried this problem:
    Evaluate 4 + 8 × 2.
    Priya wrote -20. That is not correct. What is the right answer?

    Answer. 20

    Priya’s answer -20 is off. Multiply first: 8 × 2 = 16. Then 4 + 16 = 20.

12. 12.

    Think

    Luis found the area of a 7 by 4 cm rectangle by adding 7 + 4. What is the actual area?

    Answer. 28 square cm

    Adding gives perimeter pieces, not area. A = ℓ × w = 7 × 4 = 28 square cm.

Original extra practice. Keys are computed from the items, not guessed.