The most common mistake
Children often start measuring from the end of the ruler, or from 1. On the printed-ruler sheets every object starts exactly at zero; on the “use your own” sheets they have to line it up themselves.
Real size
Every sheet is drawn to scale, so the objects are as long on paper as their measurements say. That makes it easy to check an answer with a real ruler.
In the Australian Curriculum
- FoundationComparing the length of objects directly, side by side.
- Year 1Measuring the length of shapes and objects with uniform informal units.
- Year 3Using familiar metric units to estimate, compare and measure length and other attributes.
In the Australian Curriculum, rulers and centimetres come after a long stretch of informal units: hand spans, paperclips or blocks laid end to end in Year 1. By Year 3 children use familiar metric units, so the printed-ruler sheets suit the move to formal units and “use your own ruler” suits Year 3 and up.
Australia uses metric units only, so keep the maker on centimetres. The inch option is there for other countries.
Summarised in our own words from the Australian Curriculum: Mathematics, Version 9.0 (ACARA).
