Maths is made up of two areas, knowledge and strategy. Maths knowledge understanding is broken up into 7 Stages.  Stage 0 is the most simplistic knowledge level and deals with simply recognising numbers 0-5 and their order. These stages build up to reach Stage 7 - the highest knowledge level which deals with fractions, decimals, square root, multiplication of 2 digit numbers etc.  Students may initially move quickly through the early stages (1-4)  but each of the later stages represents about two years worth of learning therefore it can deceptively look like their progress is slowing.