Page 187 - DK Children's Encyclopedia

Numbers SEE ALSO

▸ ▸ Clocks p.61
▸ ▸ Coding p.65
Numbers are symbols that can be used to show amounts, ▸ ▸ Codes pp.66–67
sizes, distances, and times. The ordinary numbers we ▸ ▸ Fractions p.112
count with are called ”whole numbers” or ”natural ▸ ▸ Measuring p.159

numbers.” All math requires us to use numbers. ▸ ▸ Temperature
p.252

Whole numbers
The numbers 0 to 9 are
used to build all the
bigger numbers. They 0 1 2 3
are called whole numbers
because they are not split
into smaller amounts.

Zero represents Whole numbers are
nothing. also called “positive”
numbers.
Negative numbers
Numbers less than zero
are called "negative"
numbers. They are -5 -4 -3 -2 -1 0 1 2 3 4 5
used to show things
less than zero, such as
cold temperatures.
Negative numbers Zero is neither Positive numbers
are shown with positive nor have no symbol
a minus sign. negative. in front.

Place value
Algebra The place where a number is written in a
Algebra is a type of math that uses letters to stand longer number shows how much it is worth.
for numbers or amounts. We can use algebra to The lowest worth, the unit, is on the right.
work out the value of unknown amounts.

2 + a = 5 4 , 5 62

The “a” represents An equals sign
a mystery number. means both
We can work out sides of the
what it is by taking equation have Thousands Hundreds Tens Units
2 away from 5. the same value. This shows how This shows how This shows how Units are
many thousands many hundreds many tens the numbers
the number has. the number has. number has. from 0–9.
185

US_185_Numbers.indd 185 05/06/2017 14:27