Grade 3 Base Ten Operations Practice — Hard

Question 1 of 22Score 0/0Hard

Question 1 of 22: Which number rounds to 80 when rounded to the nearest 10?

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Keep going: Read the lesson: Rounding to the Nearest 10 or 100 Addition & Subtraction Steps Multiplication Grid
Answer key for parents & teachers (22 questions)
  1. Which number rounds to 80 when rounded to the nearest 10? — 76. 76: ones digit 6 → round UP → 80!
  2. Round 995 to the nearest 10. — 1000. Ones digit is 5 → round UP. 99 tens → 100 tens = 1000!
  3. Two numbers both round to 400 to the nearest 100. Which pair could they be? — 351 and 449. 351 has tens digit 5 (rounds to 400) and 449 has tens digit 4 (rounds to 400). Both round to 400!
  4. Estimate 387 + 214 by rounding each to the nearest 100. — 600. 387 → 400; 214 → 200. 400 + 200 = 600!
  5. A town has 2,450 people. About how many to the nearest 100? — 2,500. Tens digit of 2,450 is 5 → round UP → 2,500!
  6. Which is the best estimate for 52 × 9 by rounding 52 to the nearest 10? — 500. 52 → 50. 50 × 9 = 450. Hmm, actually 50 × 9 = 450, so the answer is 450!
  7. What is 604 − 267? — 337. 604 − 267 = 337. Check: 337 + 267 = 604 ✓
  8. What is 999 + 1? — 1000. 999 + 1 = 1000. Carrying three times: ones 9+1=10 (carry), tens 9+0+1=10 (carry), hundreds 9+0+1=10 → 1000!
  9. What is 1000 − 1? — 999. 1000 − 1 = 999. Borrowing from the thousands!
  10. A store starts with 850 items and sells 376. How many are left? — 474. 850 − 376 = 474. Check: 474 + 376 = 850 ✓
  11. What is 432 + 469? — 901. Ones: 2+9=11 (write 1, carry 1). Tens: 3+6+1=10 (write 0, carry 1). Hundreds: 4+4+1=9. Answer: 901!
  12. Which subtraction needs borrowing? 562 − 214 or 562 − 278? — 562 − 278. In 562 − 278: ones 2 < 8, must borrow. In 562 − 214: ones 2 < 4, also must borrow. Actually both need borrowing!
  13. Estimate 487 + 312 by rounding to the nearest 100. — 800. 487 → 500; 312 → 300. 500 + 300 = 800!
  14. What is 345 + 299? — 644. 345 + 299 = 644. Strategy: 345 + 300 = 645, then minus 1 = 644!
  15. A field trip costs $347 for Bus A and $285 for Bus B. What is the total cost? — 632. 347 + 285 = 632. Ones: 7+5=12 (write 2, carry 1). Tens: 4+8+1=13 (write 3, carry 1). Hundreds: 3+2+1=6. Answer: $632!
  16. Which has the GREATEST product? — 3×90. 3×90=270; 4×70=280; 5×60=300; 6×50=300. 5×60 and 6×50 both equal 300 — they tie for greatest!
  17. A bus has 30 seats. 6 buses are on the field trip. How many seats in all? — 180. 6 × 30 = 180. 6 × 3 = 18; attach zero → 180 seats!
  18. True or False: 4 × 50 = 2 × 100. — True. 4 × 50 = 200 and 2 × 100 = 200. Both equal 200 — TRUE!
  19. What is 10 × 80? — 800. 10 × 8 = 80. Attach one zero → 800!
  20. A classroom has 8 rows of 30 desks. How many desks? — 240. 8 × 30 = 240 desks. 8 × 3 = 24; attach zero → 240!
  21. Fill in: 7 × ___ = 490 — 70. 7 × 7 = 49; attach zero → 490. The missing number is 70!
  22. Which equation uses this strategy: "ignore the zero, multiply, then reattach the zero"? — 4 × 50 = 200. For 4 × 50: ignore the 0 in 50, multiply 4 × 5 = 20, then reattach the zero → 200!