Introduction

Explore the composition of 1,000 and four-digit numbers, using the partitioning structure, and make links to measures; introduce children to calculation across thousands boundaries, and extend column algorithms and rounding to four-digit numbers.

Teaching points

• Teaching point 1: Ten hundreds make 1,000, which can also be decomposed into 100 tens and 1,000 ones.
   
• Teaching point 2: When multiples of 100 are added or subtracted, the sum or difference is always a multiple of 100.
   
• Teaching point 3: Numbers over 1,000 have a structure that relates to their size. This means they can be ordered, composed and decomposed.
   
• Teaching point 4: Numbers can be rounded to simplify calculations or to indicate approximate sizes.
   
• Teaching point 5: Calculation approaches learnt for three-digit numbers can be applied to four-digit numbers.
   
• Teaching point 6: 1,000 can also be composed multiplicatively from 500s, 250s or 200s, units that are commonly used in graphing and measures.