Diag · Diagnostic set

1. 1.

   Find the area of a rectangle with length 7 cm and width 8 cm.

   Answer. 56 square cm

   A = ℓ × w = 7 × 8 = 56 square cm.

2. 2.

   Compute 18 × 34. Write the product in simplest form.

   Answer. 332

   18 × 34 = 332 = 332.

3. 3.

   Evaluate 6 × (3 − 6).

   Answer. -18

   Parentheses first: 3 − 6 = -3. Then 6 × -3 = -18.

4. 4.

   Find 7.9 × 5.

   Answer. 39.5

   7.9 × 5 = 39.5.

5. 5.

   Evaluate 7 + 7 × 4. Then Grace needs 2 of that amount. What is the total they need?

   Answer. 70

   Multiply first: 7 × 4 = 28. Then 7 + 28 = 35. Then multiply by 2: 70.

6. 6.

   Theo is covering 2 identical garden beds. Each is 82 cm by 6 cm. What total area must be covered?

   Answer. 48 square cm

   One area is 24. 2 of them: 24 × 2 = 48 square cm.

7. 7.

   A pan is 23 full of brownies. Priya eats 25 of what is in the pan. How much of a whole pan did Priya eat?

   Answer. 415

   23 of a pan, then 25 of that: 23 × 25 = 415.

8. 8.

   Malik has 4 packs of 7 stickers and gives 6 stickers away. Evaluate 4 × 7 − 6 to find how many are left.

   Answer. 22

   Multiply first: 4 × 7 = 28. Then 28 − 6 = 22.

9. 9.

   Find 5.4 × 8. Then Malik needs 2 of that amount. What is the total they need?

   Answer. 86.4

   5.4 × 8 = 43.2. Then multiply by 2: 86.4.

10. 10.

    Evaluate 2 + 5 × 5. Then Mei needs 2 of that amount. What is the total they need?

    Answer. 54

    Multiply first: 5 × 5 = 25. Then 2 + 25 = 27. Then multiply by 2: 54.

11. 11.

    Think

    Sam found the area of a 13 by 4 cm rectangle by adding 13 + 4. What is the actual area?

    Answer. 52 square cm

    Adding gives perimeter pieces, not area. A = ℓ × w = 13 × 4 = 52 square cm.

12. 12.

    Think

    Luis computed 12 × 13 by adding and got 56. What is the actual product in simplest form?

    Answer. 16

    Multiply numerators and denominators, then simplify: 16 = 16.

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