Fractions and Decimals

Introduction

We use fractions to indicate partial amounts. They are not just used in mathmatics but also in recipes (½ litre water). Decimals are separated by a decimal point.

Construction

We use both cardinal and ordinal numbers to create fractions. The numerator (the numeral above the line) is always a cardinal number. The denominator (the numeral below the line) is always an ordinal number.

1/3 one third 1/10 one tenth
1/5 one fifth 1/20 one twentieth
1/6 one sixth 1/100 one hundredth
1/8 one eighth 1/1000 one thousandth

Exceptions:

1/2 one half
1/4 one quarter

Numerators Greater Than One

When a numerater is greater than one, we use the denominator in plural (we add an s).

2/3 two thirds 2/7 two sevenths
3/4 three quarters 4/8 four eighths
4/5 four fifths 5/10 five tenths
3/6 three sixths 6/12 six twelfths

Writing Fractions

Fractions can be written in two different ways:

  • There is a slash bewteen the two numerals.
    Example:
    2/5 – two fifths
    7/3 – seven thirds
  • The numerals are written on top of each other and are separated by a horizontal line. (this variant is mostly used in mathmateics)
    Example:
    2/525 – two fifths
    7/373 – seven thirds

Decimal Numbers

Decimal numbers are written with a decimal point. The digits after the decimal point are said separately.

Example:
0.135 – nought point one three five (US: zero point one three five)
3.14159 – three point one four one five nine

Singular and Plural with Fractions and Decimals

If we want to say exactly what the fraction or decimal refers to and the value is less than one, we use the contruction of a + singuar noun. (except for 1/2, see last example)

Example:
3/4 T → three quarters of a ton
2/3 km → two thirds of a kilometre
0.743 cm → nought point seven four three of a centimetre
1/2 l → half a litre (not: one half of a litre)

If the value of the fraction or decimal is greater than one, the numeral is followed directly by a plural noun.

Example:
one and a half hours
three and a quarter kilos
2.5 millimetres