Rounding off to nearest Thousand (1000)
For number 2031,
Rounding off to nearest Thousand means
We write number as 2000 or 3000
Since 2000 is near to 2031
So, 2031
In general,
Thus
2851 → 3000
2918 → 3000
2500 → 3000
2501 → 3000
2499 → 2000
2281 → 2000
General rule for rounding off
General rule says
For a number in tens, we round off to tens.
For a number in hundred, we round off to hundred.
For a number in thousands, we round off to thousands.
Eg:
479 × 81
According to general rule,
479 is rounded off to nearest hundred
∴ 479 → 500
81 is rounded off to nearest ten
∴ 81 → 80
So, Estimated Product = 500 × 80
= 5 × 100 × 8 × 10
= (5 × 8) × 1000
= 40 × 1000
= 40000
Eg 2:
37 × 1889
According to general rule,
37 is rounded off to nearest ten
∴ 37 → 40
1889 is rounded off to nearest thousand
∴ 1889 → 2000
So, Estimated Product = 40 × 2000
= 4 × 10 × 2 × 1000
= (4 × 2) × 10000
= 8 × 10000
= 80000
Eg 3:
232 + 4821
According to general rule,
232 is rounded off to nearest hundred
∴ 232 → 200
4821 is rounded off to nearest thousand
∴ 4821 → 5000
So, Estimated Sum = 200 + 5000
= 5200
Eg 4:
1089 + 6871
According to general rule,
1089 is rounded off to nearest thousand,
∴ 1089 → 1000
6871 is rounded off to nearest thousand,
∴ 6871 → 7000
∴ Estimated Sum = 1000 + 7000
= 8000
Eg 5:
9560 − 421
According to general rule,
9560 is rounded off to nearest thousand,
∴ 9560 → 10,000
421 is rounded off to nearest hundred,
∴ 421 → 400
∴ Estimated Difference = 10,000 – 400
= 9600

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.