Decimal numbers

Decimal numbers such as 3.14 are used in situations in which we look for more precision than whole numbers provide. As with whole numbers, a digit in a decimal number has a value which depends on the place of the digit.

Note that adding extra zeros to the right of the last decimal digit does not change the value of the decimal number.

In the number 3.14, 3 is called the whole number portion and 14 is called the decimal portion.

We have to read the whole number, then the word “point” and the decimal numbers one by one:
- In the number 2.34 we say two point three four
- We read the number 0.057 as zero point zero five seven, or point zero five seven only. (zero = nought)

Exercises:

1.- How do you read these numbers?
a) 134.27

b) 0.023

c) 0.45

d) 0.001

2.- Write these numbers:
a) Twenty units and two tenths
b) Two hundredths
c) Three units and forty-three thousandths
d) Eighty millionths

Solutions:

1.- a) One hundred and thirty four point two seven; b) point zero two three; c) point four five; d) one thousandth

2.- a) 20.2; b) 0.02; c) 3.043; d) 0.00008