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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Decimal Places (d.p)
A number such as 270.8143 is an example of a decimal number.
To find the number of decimal places (d.p) simply count the number of figures after the decimal point. Thus, this number has 4 d.p.
Find the number of decimal places in the following numbers.
a) 47.04 -> 2 d.p
b) 0.395 -> 3 d.p
d.p. means decimal places.
Rounding Off Numbers | Specific Number of Decimal Places:
Sometimes, it is useful to round decimal numbers to a specific number of decimal places or to the nearest whole number.
To round a decimal number to a given number of decimal places:
1. Look for the last digit (i.e. the required decimal place you are rounding to)
2. Then look at the next digit to the right i.e. the decider.
3. If the decider is 5 or more round up (i.e. add 1 to the last digit) if it is less than 5, then add nothing.
Give the number 58.07526 correct to:
a. 1 d.p
b. 3 d.p.
|1 d.p||2 d.p||3 d.p||4 d.p||5.dp|
The number that represents 1 d.p in this example is 0. The next digit to the right (the decider) is 7 which is greater than 5. So we add 1 to 0 in this example.
i.e. add 1 to the 1st d.p. i.e. 0 + 1 = 1
Therefore, 58.07526 = 58.1 correct to 1 d.p.
|1 d.p||2 d.p||3 d.p||4 d.p||5 d.p|
The number that represents 3 d.p in this example is 5. The next digit to the right the decider) is 2 which is less than 5. So we add nothing.
Therefore, 58.07526 = 58.075 to 3 d.p
Now try this for yourself
Give the number 0.0164
a. 2 decimal places
b. 3 decimal places
a. 0.0164 = 0.02 correct to 2 d.p
b. 0.0164 = 0.016 correct to 3 d.p