Estimate it
Round 28 × 43 to the nearest tens and estimate the product.
30 × 40 = 1,200
Round both factors before multiplying.
What is 30 × 40?
1200
Break apart 24 × 13 using the distributive property.
(20 + 4) × (10 + 3)
There are 6 shelves with 17 books each. How many books?
CORRECT ANSWER
102 books
6 × 17 = 102.
A poster is 12 inches by 15 inches. What is its area?
180
A farmer plants 19 rows with 31 seeds in each row. About how many seeds?
20 × 30 = 600 seeds
The word 'about' tells us to estimate.
Find the missing factor: 50 × ___ = 3,500.
70
Find 32 × 14 using partial products.
448
300 + 120 + 20 + 8 = 448.
A shop has 8 shelves with 16 plants each. It adds 3 more shelves. How many plants now?
176 plants
(8 + 3) × 16 = 176.
A florist makes 23 arrangements with 14 flowers each. How many flowers?
322 flowers
23 × 14 = 322.
Estimate 47 × 62 by rounding to the nearest tens.
50 × 60 = 3,000
47 rounds up; 62 rounds down.
Find the missing factor: 80 × ___ = 5,600.
70
(20 + 7) × (10 + 5). Find all four partial products.
200, 100, 70, 35
Each necklace uses 24 beads. How many beads are needed for 30 necklaces?
720 beads
24 × 30 = 720.
A class makes 13 rows of 16 lanterns and 12 rows of 18 lanterns. How many lanterns altogether?
424
A florist makes 29 bouquets with 18 flowers each. Use compatible numbers to estimate the total.
About 600 flowers (30 × 20)
Which equals 420: 21 × 20 or 21 × 200?
21 × 20 = 420
Which expressions equal 360?
A: 18×20;
B: 10×20+8×20;
C: 18×2;
D: 20×20−40.
A, B, and D
A craft club has 960 beads and uses 24 beads per bracelet. How many bracelets can it make?
40 bracelets
24 × 40 = 960.
One painting measures 28 × 24 inches. Another measures 16 × 12 inches. What is the difference in their areas?
480 square inches
672 − 192 = 480.
A museum sells 38 tickets each hour for 24 hours. Estimate, then explain whether the estimate is greater than the exact answer.
40 × 20 = 800; the exact answer is 912, so the estimate is less.
A product is 7,200. One factor is 90. What is the other factor?
80; 90 × 80 = 7,200
Find 46 × 23 using partial products.
1,058
800 + 120 + 120 + 18 = 1,058.
A landscaping company charges $65 per tree. It plants 14 trees Monday and 26 Tuesday. How much does it charge altogether?
$2,600
(14 + 26) × 65 = 2,600.
A school orders 18 boxes with 24 pencils each and 15 boxes with 32 pencils each. How many pencils altogether? Explain both operations.
912 pencils
18×24=432 and 15×32=480; add because the question asks for the combined total.