One More and One Less: Finding the Number Just After and Just Before

You will meet this idea in ordinary days. One more and one less happen at every meal and every game. One more plate arrives when a guest comes. One less apple sits in the bowl after your brother takes one.

This is worth learning because adding one and taking one away are the smallest and most useful moves in math.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Watch this carefully, friend. Every number has a neighbor on each side. One more means the next number when you count forward. One less means the number you say just before it.

For seven, one more is eight and one less is six. You can find these on your fingers or on a number line. Picture the numbers standing in a line like children waiting their turn. Ask yourself who stands right behind and who stands right in front. Try this out loud.

One more than nine is ten. One less than ten is nine. Notice how those two facts use the same pair of numbers from opposite directions. If one more feels easy but one less feels hard, practice counting backward from twenty a few times each day. If you get stuck, use your fingers or counters. Good mathematicians use tools.