Students need to understand that counting numbers and numbers obtained by measurement behave in the same way (for example: adding two identical lengths gives the same result as doubling one of the lengths; finding the difference in length is the same as subtracting one length from another). This means that students can continue to develop their number skills and knowledge in contexts that involve measurement, and vice versa.
Once students understand that there is nothing you can do with counted numbers that you can’t also do with numbers obtained by measurement, they can tackle measurement problems with growing confidence. This understanding is particularly useful when solving word problems.
Many students find word problems challenging: they need to be able to read and comprehend the text, identify what they are being asked to do, and then convert the challenge into numbers, symbols, and processes. Students who struggle to get over the language hurdle sometimes resort to randomly adding or multiplying numbers without understanding what they need to do or which operation is appropriate.
Numeracy Development Project Book 5 identifies four types of additive problems: join, separate, combine, and compare. Helping students to identify these four patterns can help them to determine in a given situation:
- what they are being asked to find
- how to organise the information they are given, and which visual models may be useful
- which operation(s) they should use to solve the problem.
Once the students understand the structure of a problem, it doesn’t matter whether the context is counting or measuring. The quantities and contexts change, but the pattern is the same.