To solve the problem, we need to estimate the difference by rounding each number to the specified place value (nearest 100s, 10s, or 1000s) and then calculate the exact difference.
(i) 765 - 412
- Rounded to nearest 100s: 800 - 400 = 400
- Exact difference: 765 - 412 = 353
(ii) 68 - 62
- Rounded to nearest 10s: 70 - 60 = 10
- Exact difference: 68 - 62 = 6
(iii) 479 - 171
- Rounded to nearest 10s: 480 - 170 = 310
- Exact difference: 479 - 171 = 308
(iv) 2361 - 1486
- Rounded to nearest 10s: 2360 - 1490 = 870
- Exact difference: 2361 - 1486 = 875
(v) 694 - 249
- Rounded to nearest 100s: 700 - 200 = 500
- Exact difference: 694 - 249 = 445
(vi) 5478 - 4006
- Rounded to nearest 100s: 5500 - 4000 = 1500
- Exact difference: 5478 - 4006 = 1472
(vii) 9010 - 5308
- Rounded to nearest 1000s: 9000 - 5000 = 4000
- Exact difference: 9010 - 5308 = 3702
(viii) 32456 - 21716
- Rounded to nearest 1000s: 32000 - 22000 = 10000
- Exact difference: 32456 - 21716 = 10740
Final Answers:
(i) Estimated: 400, Exact: 353
(ii) Estimated: 10, Exact: 6
(iii) Estimated: 310, Exact: 308
(iv) Estimated: 870, Exact: 875
(v) Estimated: 500, Exact: 445
(vi) Estimated: 1500, Exact: 1472
(vii) Estimated: 4000, Exact: 3702
(viii) Estimated: 10000, Exact: 10740
Parent Tip: Review the logic above to help your child master the concept of estimating sums and differences worksheet.
