3.8 Order of decimal calculations
The same rules about the order of calculations apply to decimals as apply to whole numbers.
Calculations are performed in the following order:
Brackets;
Powers (e.g. squaring or cubing a number);
Division and Multiplication (performed in the order written, left to right);
Addition and Subtraction (performed in the order written, left to right).
Example 19
Calculate 3.5 + 0.7 × 8 ÷ (4.6 − 2.6).
Answer
Brackets first: 4.6 − 2.6 = 2.0, so calculate 3.5 + 0.7 × 8 ÷ 2.0.
Multiply next: 0.7 × 8 = 5.6, so calculate 3.5 + 5.6 ÷ 2.0.
Divide next: 5.6 ÷ 2 = 2.8, so calculate 3.5 + 2.8.
Lastly add: 3.5 + 2.8 = 6.3.
So the answer is 6.3.