Step 1 Objective

Describe and extend number sequences: count on or back in tens or hundreds, starting from any two- or three-digit number.

Examples of what pupils should know and be able to do

First with and then without a 1-100 grid:

Without a grid:

Probing questions

If you count in tens from 42, which digit changes? Why doesn't the ones digit change?

If you start with 93 and count back in tens, what would be the smallest number you would reach on a 1-100 grid? Would 14 be one of the numbers you say? Why not?

What do you notice when I subtract 10 from a number? Can you explain?

What if pupils find this a barrier?

Give pupils a 1 - 100 grid (or use Number Grid ITP - Zip file (462Kb)) and ask them to start from 5 and chant all the numbers moving vertically down the column. What is the same and what is different about these numbers? Why?

Start at 92 and move vertically up. What is happening now?

Repeat for different numbers.

Continue without the grids, counting on and back in tens and hundreds. Make this a regular feature of pre-starters for lessons.

Number Grid ITP - Zip file (462Kb) is useful for counting on and back in tens.