One more, one less
Maths · Early Years · The School
The next number along
One more means the very next number when you count up. One more than 4 is 5. One more than 7 is 8. You already know this — it is just counting! The trick is starting from the number you are given instead of going back to one every time. Say it out loud: "four... five. One more than four is five."
Counting back
One less means the number just before. One less than 6 is 5. Counting backwards is harder than forwards, so practise the backwards count on its own: ten, nine, eight, seven, six, five, four, three, two, one. Sing it, march it, use your fingers — the backwards count is the tool you will need for taking away later.
The number line helps
Draw the numbers 0 to 10 in a line. One more is a step to the RIGHT. One less is a step to the LEFT. Put your finger on 6 and step right — you land on 7. Step left twice from 6 and you land on 4. A number line turns adding and taking away into moving, and moving is easy to see.
Say the counting order and listen for what comes after eight: six, seven, eight, NINE. That is one more. Check it on the number line: put your finger on 8 and step one to the right — you land on 9. Check it with objects: eight cubes, add one more, count them all — nine. Three different ways, one answer, and the first way is fastest once you trust it. Now do one LESS than 8: what comes just before? Seven.