Estimate each of the following using general rule:
(a) 730 + 998 (b) 796 – 314 (c) 12,904 +2,888 (d) 28,292 – 21,496
Make ten more such examples of addition, subtraction and estimation of their outcome.
Solution (a)
730 + 998
Rounding off 730 to the nearest hundreds we get, 700
And rounding off 998 to the nearest hundreds we get, 1,000
Therefore, 700 + 1000 = 1,700
Therefore, estimate of 730+998 is equal to 1,700 according to the general rule.
Solution (b)
796 – 314
Rounding off 796 to the nearest hundreds we get, 800
And rounding off 314 to the nearest hundreds we get, 300
Therefore, 800 – 300 = 500
Therefore, estimate of 796 – 314 is equal to 500 according to the general rule.
Solution (c)
12,904 +2,888
Rounding off 12,904 to the nearest thousands we get, 13,000
And rounding off 2,888 to the nearest thousands we get, 3000
Therefore, 13,000 + 3,000 = 16, 000
Therefore, estimate of 12, 904 + 2,888 is equal to 16,000 according to the general rule.
Solution (d)
28,292 – 21,496
Rounding off 28,292 to the nearest thousands we get, 28,000
And rounding off 21,496 to the nearest thousands we get, 21,000
Therefore, 28,000 – 21,000 = 7,000
Therefore, estimate of 28,292 – 21,496 is equal to 7,000 according to the general rule.
Example (i)
478 -312
Rounding off 478 to the nearest hundreds we get, 500
And rounding off 312 to the nearest hundreds we get, 300
Therefore, 500 – 300 = 200
Therefore, estimate of 478-312 is equal to 200 according to the general rule.
Example (ii)
425+675
Rounding off 425 to the nearest hundreds we get, 400
And rounding off 675 to the nearest hundreds we get, 700
Therefore, 400+700 = 1100
Therefore, estimate of 425+675 is equal to 1100 according to the general rule.
Example (iii)
5,125-4,213
Rounding off 5,125 to the nearest thousands we get, 5,000
And rounding off 4,213 to the nearest thousands we get, 4,000
Therefore, 5, 000-4,000 = 1,000
Therefore, estimate of 5,125-4,213 is equal to 1,000 according to the general rule.
Example (iv)
5,148-578
Rounding off 5,148 to the nearest thousands we get, 5,000
And rounding off 578 to the nearest hundreds we get, 600
Therefore, 5,000-600 = 4,400
Therefore, estimate of 5,148-578 is equal to 4,400 according to the general rule.
Example (v)
2258-647
Rounding off 2,258 to the nearest thousands we get, 2000
And rounding off 647 to the nearest hundreds we get, 600
Therefore, 2,000-600 = 1,400
Therefore, estimate of 2,258-647 is equal to 1,400 according to the general rule.
Example (vi)
5,045-512
Rounding off 5,045 to the nearest thousands we get, 5000
And rounding off 512 to the nearest hundreds we get, 500
Therefore, 5,000-500 = 4,500
Therefore, estimate of 5,045-512 is equal to 4,500 according to the general rule.
Example (vii)
412-325
Rounding off 412 to the nearest hundreds we get, 400
And rounding off 325 to the nearest hundreds we get, 300
Therefore, 400-300 = 100
Therefore, estimate of 412-325 is equal to 100 according to the general rule.
Example (viii)
10,215+4878
Rounding off 10,215 to the nearest thousands we get 10,000
And rounding off 4,878 to the nearest thousands we get, 5,000
Therefore, 10,000+5,000 =15,000
Therefore, estimate of 10,215+4,878 is equal to 15,000 according to the general rule.
Example (ix)
777+333
Rounding off 777 to the nearest hundreds we get, 800
And rounding off 333 to the nearest hundreds we get, 300
Therefore, 800 + 300 = 1,100
Therefore, estimate of 777+333 is equal to 1,100 according to the general rule.
Example (x)
247+789
Rounding off 247 to the nearest hundreds we get, 200
And rounding off 789 to the nearest hundreds we get, 800
Therefore, 200 + 800 = 1,000
Therefore, estimate of 247+789 is equal to 1,000 according to the general rule.
Nirmala Melli says
Nice
Mistha says
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Shamim akhtar says
Very good solution
Shafin Ahmad says
Thank and good solution
Shagun says
So good
Sroysi says
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Gargi Sinha says
Same 😃
Jasmine says
Good solution 👍
Vivaan Adani says
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Sampriti Mohanty says
Nice answers.
Khan says
Good 👌
Sahasra says
It was very helpful to me!