Understand common Year 1 one more and one less mistakes, why they happen and how to fix them with short practice checks.
These are common ways children can become stuck on this type of question. Use the short check after each one to make sure the correction is understood.
Why it happens: A digit can represent a different value depending on its position, which matters in one more and one less.
Fix it: Name the place first (ones, tens, hundreds and so on), then state the digit's value.
Why it happens: Crossing a tens, hundreds or larger boundary can make a sequence look less familiar.
Fix it: Say the sequence aloud and mark the boundary number before continuing.
Why it happens: The largest place determines which whole number is greater.
Fix it: Compare from the leftmost place and stop at the first place that differs.