How_To_Be_Good_At_Math

78 CALCULATING •^ ADDITION

Addition

When we bring two or more quantities together to make a

larger quantity, it’s called addition or adding. There are two

ways to think about how addition works.

What is addition?

Look at these oranges.

When we combine

6 oranges and 3 oranges,

there are 9 oranges

altogether. We can

say we have added

6 oranges and 3 oranges,

which equals 9 oranges.

6

• 
  

  =

  
  


• 
  

  3 =

  
  

This symbol means

add or plus

This symbol

means

equivalent to,

or equals

Combining 6 oranges and

3 oranges gives us 9 oranges

9

Adding works in any order

It doesn't matter which way we add amounts.

The total will be the same. We say that

addition is commutative.

Now let’s switch the

numbers around on the

left-hand side of the equals

sign. It doesn’t matter which

order we add numbers, the

total will be the same.

Look at this

calculation. It says that

if we add 2 to 5, we get 7.

REAL WORLD MATHS

The ancient calculator

The earliest type of calculator was

the abacus, used in ancient Egypt,

ancient Greece, and other places

around the world. The abacus

helped people calculate amounts,

with beads on different rows used

to represent different numbers, like

5 2 = 7 ones, tens, and hundreds.

2 + 5 = 7

It doesn’t matter which

way you add numbers

together. The answer

will be the same.

• =

=

078_079_Addition.indd 78 29/02/2016 18:56