Step by step
The question
Question: work out 20 ÷ (1 + 3) − 2² × 2.
20 ÷ (1 + 3) − 22 × 2
1 Brackets first
Brackets come first.
Order: ( ) → x² √ → × ÷ → + −
1 plus 3 is 4.
= 20 ÷ 4 − 22 × 2
2 Powers
Powers come before divide, minus and times.
2² means 2 times 2.
22 = 2 × 2 = 4
That is 4.
= 20 ÷ 4 − 4 × 2
3 Times and divide
Dividing comes before minus.
Times and divide: we go from left to right.
same kind: left → right
20 divided by 4 is 5.
= 5 − 4 × 2
Times comes before minus.
4 times 2 is 8.
= 5 − 8
4 Plus and minus
We take away more than we have.
Start at 5.
Go down 8.
We pass 0 and land on −3.
= −3
So the answer is −3.
Let's look back.
First: brackets first.
Then: powers.
Then: times and divide.
Last: plus and minus.
Answer
= −3