Identify, represent and estimate numbers using different representations, including the number line

What this means, in plain words

Estimating means reaching an answer close enough to be useful, before or instead of calculating it exactly.

A number line puts numbers in order along a line, evenly spaced, so larger and smaller can be seen rather than worked out.

Representing means showing the same maths another way, with objects, a picture or a bar model, so the structure becomes visible.