# NA5-3: Understand operations on fractions, decimals, percentages, and integers.

This means students will understand calculations involving fractions, decimals, percentages and integers. It assumes accuracy in calculation and the exercising of appropriate choice between mental, written and machine methods given the complexity of the numbers involved and the significance of the calculation in the context of the problem. Understanding also implies the prudent use of estimation to check the reasonableness of calculations and as an end in itself where approximations are sufficient.

Students should be able to explain the calculation steps (procedures) they followed and justify those steps by describing the quantities involved. For example, the calculation 1.4 x 0.6 = 0.84 might be justified as 14/10 x 6/10 = 84/100 or 14 x 6 = 84 and the size of answer being about half of 1.4.

The problems solved should involve result unknown, for example 56% of 38 = , change unknown, for example % of 38 = 21.28, or start unknown, for example 56% of = 21.28.