The additive inverse of a number is a number that, when added to the original number, gives the sum of 0.

An operation is commutative if the values it is operating on can be written in either order without changing the calculation.

Priority of operations with positive integers

Maths

Pupils use their understanding of place value and fluency with decimals from this unit in order to extend this understanding to fractions.  In the future unit, pupils will be asked to compare and order both fractions and decimals and will assess when conversion is required.

The prior unit on factors, multiples, squares and cubes helped pupils build on their understanding that any positive integer can be expressed as a product of its factors. This skill is used here to explore multiplying and dividing with decimals.

Arithmetic procedures with integers and decimals

This image is a help guide to the priority of operations. Which set of operations must you always apply first when they are in a calculation?

How would you complete a calculation when an operation is repeated?

Without using a calculator, work out: $$4\times5  + 6\times7$$ = {{ }}

Without using a calculator, work out: $$200\;-(12\;–\;8)\times5\times3^2$$ = {{ }}

The answer to this calculation is 54. Match the triangle, star, square and arrow to the correct operation or numerical value.

Without using a calculator, work out: $$90 + \sqrt{40\times10}-12\times5$$ = {{ }}

when added to the original number, gives the sum of 0

when added to the original number, gives the sum of 1

when multiplied by the reciprocal the product is 1

when multiplied by the reciprocal the product is (-1)

Complete the statement. The additive inverse of a number is a number that, __________

Match each number with its additive inverse.

Select all the fractions that are equivalent to $${2} \over {3}$$.

Match each calculation with an equivalent commutative calculation.

Work out the missing number: $$9.8 \times 0.5 + 9.8 \times$$ {{ }} $$= 9.8$$

Work out the missing number: $$34 \times 0.8 + 34 \times$$ {{ }} $$= 68$$

This lesson will soon be taken down.

Priority of operations with positive integers

Lesson outcome