JSS1: MATHEMATICS - 1ST TERM
Whole Numbers I | Week 13 Topics|1 Quiz
Whole Numbers II | Week 21 Topic|1 Quiz
Counting in Base Two | Week 34 Topics|1 Quiz
Arithmetic Operations | Week 43 Topics|1 Quiz
Lowest Common Multiple (LCM) | Week 52 Topics|1 Quiz
Highest Common Factor | Week 61 Topic|1 Quiz
Fraction | Week 77 Topics|1 Quiz
Basic Operations with Fractions I | Week 83 Topics|1 Quiz
Basic Operations with Fractions II | Week 91 Topic|1 Quiz
Directed Numbers | Week 103 Topics|1 Quiz
Estimation and Approximation I | Week 113 Topics|1 Quiz
Estimation and Approximation II | Week 126 Topics|1 Quiz
Rounding Decimals to the Nearest Tenth, Hundredth & Thousandth
Rounding Decimal Numbers to the Nearest Whole Number
Significant Figures (S.F.)
Numbers less than Zero
Approximation Involving the Four Basic Operation
- Rounding Decimals to the Nearest Tenth, Hundredth & Thousandth
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Rounding Off Numbers
Rounding means making a number simple but keeping its value close to what it was. The result may be less accurate, but easier to use.
There are many ways to round. This is the most common method:
1. Decide which is the last digit to keep.
2. Leave it the same if the next digit is less than 5 (this is called rounding down)
3. Increase it by 1 if the next digit is 5 or more (this is called rounding up).
i. Round 2345 to the nearest 10
ii. Round 1734 to the nearest 100.
iii. Round to the nearest thousand
(a) 14 514
(b) 3 453 16
i. 2345 to nearest ten
5 unit is rounded up
The number in the tens increases by 1.
Hence 2 3 4 5 to nearest Ten is 2350.
ii. Round 1734 to nearest Hundred.
3 is less than 5 so round down
Hence 1734 to the nearest hundred = 1700.
iii. (a) 14 514 to nearest thousand.
4 represents thousand here and the number next to it is 5 so we add 1 to 4
Therefore, 14514 = 15000 to the nearest thousand.
iii. (b) 3453165 to nearest thousand.
3 represents thousand here and the number next to it is 1 which is less than 1 so we round down
Therefore, 3 453165 = 3 453 000.