Worked example 2 (i) Round 456 327 to three signifi cant fi gures.
Solution (i)
(ii) Round 638·29 to two signifi cant fi gures.
(ii)
Converting fractions to decimals As discussed in 5.1, a fraction is a number written in the form of one number divided by another number.
To convert a fraction to a decimal, we divide the numerator (top) by the denominator (bottom). Your calculator will display this answer in what is known as standard form, i.e. as a fraction. To convert from standard form to decimal form we can use the standard to decimal button.
Converting decimals to fractions Put the decimal over 1.
1
2 3
Multiply the numerator and the denominator by 10 for every number after the decimal point. Express the fraction in its simplest form.
For example, 0·17 = 0·17
____ 1 = 0·17 × 10 × 10
Worked example 3 (i) Convert 2
__ 5 into a decimal.
Solution (i)
___________ 1 × 10 × 10 = 17
___ 100
(ii) Convert 0·375 into a fraction.
(ii)
Practice questions 5.3
1. State whether each of the following decimals are terminating, recurring or neither. Justify your answer in each case. (i) 0·5 7