LESSON 22: WHOLE NUMBERS

• Counting, ordering, comparing and representing, and place value of digits (4-digit

whole numbers)

• Addition and subtraction (4-digit whole numbers)

You must be able to do the following with whole numbers:

Count on and back in 2s, 3s, 5s, 10s, 25s, 50s and 100s – between 0 and 10000. • Order, describe and present 4-digit whole numbers. • Compare and represent even and odd numbers up to 1 000. • Recognise place values of 4-digit whole numbers. • Round to the nearest 10, 100 or 1000.

Take your time and go through the requirements with your facilitator. Revise these concepts and make sure that you have mastered all of them. In the next part of this lesson you will need to do and apply these requirements. Page back to lesson 1 and lesson 10 to refresh your memory.

We are now going to use 4-digit numbers to add and subtract whole numbers.

You must be able to use the following techniques when doing calculations:

• Estimation • Building up and breaking down numbers • Rounding and compensation • Doubling and halving • Using a number line • Using addition and subtraction as inverse operations to test your answers

By now you should be comfortable with all of the above techniques. If you are still uncertain about which technique to use, you now have the opportunity to practise and master the technique. If you have forgotten how to use any of the techniques, page back to lesson 9 in unit 1, and lessons 11 and 18 in unit 2 to refresh your memory.