7. Decimal operations

Lesson

In earlier lessons we have learned the order of operations. Have a look at the following problem and be sure to use the correct order of operations.

Find the value of 12 \times \left(5+6\right) -35

Worked Solution

Idea summary

The order of operations:

Solve anything inside grouping symbols (brackets).

Solve any multiplication or division, including powers, working from left to right.

Solve any addition or subtraction, working from left to right.

This video shows some examples of working out the value of an expression that involve decimals and 2 operations.

Find the value of 8.5+0.65\times10.

Worked Solution

Idea summary

The order of operations is the same for decimals as it is for whole numbers.

This video shows some examples of working out the value of an expression that involve decimals and 3 operations.

Find the value of 0.6\times8-0.6\times4, giving your answer as a decimal.

Worked Solution

Idea summary

When solving expressions with more than one operation, we have to follow the order of operations, this includes expressions with decimals.

This video shows how to enter calculations with decimals on a calculator.

Consider 11.59\div4.44

a

Estimate the answer by rounding both values to the nearest whole number.

Worked Solution

b

Use a calculator to evaluate 11.59\div4.44 and write the answer below. Give your answer to two decimal places.

Worked Solution

c

What is the difference between the estimate and the actual answer?

Worked Solution

Idea summary

We can use calculators to make calculations with decimals easier. The calculator also uses the order of operations.

Add and subtract decimals, with and without digital technologies, and use estimation and rounding to check the reasonableness of answers

Multiply decimals by whole numbers and perform divisions by non-zero whole numbers where the results are terminating decimals, with and without digital technologies