Multi-Digit Multiplication — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. 36 × 45 = 1,620
Using partial products: 36 × 5 = 180 and 36 × 40 = 1,440. Adding gives 180 + 1,440 = 1,620.
2. A school cafeteria serves 47 lunches per day. In 22 school days the cafeteria serves 1,034 lunches.
Multiply 47 × 22: 47 × 2 = 94 and 47 × 20 = 940, so 94 + 940 = 1,034 lunches served over 22 days.
3. 81 × 19 = 1,539
Using partial products: 81 × 9 = 729 and 81 × 10 = 810. Adding gives 729 + 810 = 1,539.
4. Estimate 63 × 38 by rounding: 60 × 40 = 2,400
Round 63 down to 60 and 38 up to 40 for a quick estimate. 60 × 40 = 2,400, which is close to the exact product of 2,394.
5. 55 × 32 = 1,760
Using partial products: 55 × 2 = 110 and 55 × 30 = 1,650. Adding gives 110 + 1,650 = 1,760.
6. The partial products of 74 × 16 are 74 × 6 = 444 and 74 × 10 = 740, so 74 × 16 = 1,184
Adding the two partial products: 444 + 740 = 1,184. This confirms that 74 × 16 = 1,184.
7. A truck carries 68 crates each trip. After 14 trips the truck has carried 952 crates.
Multiply 68 × 14: 68 × 4 = 272 and 68 × 10 = 680, so 272 + 680 = 952 crates carried in 14 trips.
8. 93 × 27 = 2,511
Using partial products: 93 × 7 = 651 and 93 × 20 = 1,860. Adding gives 651 + 1,860 = 2,511.
9. 49 × 53 = 2,597
Using partial products: 49 × 3 = 147 and 49 × 50 = 2,450. Adding gives 147 + 2,450 = 2,597.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
67 × 14
→ 938
899
31 × 29
→ 899
986
58 × 17
→ 986
938
43 × 32
→ 1,376
1,376
Verify each with partial products: 67 × 14 = 67 × 4 + 67 × 10 = 268 + 670 = 938; 31 × 29 = 899; 58 × 17 = 986; 43 × 32 = 1,376.