39 and one more is not 310
A child who has only ever done 34 + 1 thinks the rule is "change the last digit". The problems that show it is not are the crossings — 39 + 1, 400 − 10, 999 + 1 — so this sheet can put one on every other line.
Look at the number, then step down and step up.
A one more, one less worksheet generator, printable as a PDF. Pick the step — one, ten, a hundred, a thousand, or any other, like 3 or 7 — and how big the numbers go, from 20 up to 10,000, or any range of your own, like 30 to 50; every number on the page, answers included, stays inside it. Each row prints a number in the middle with a box either side for the number that much less and that much more. Set crossings to lots and about half the page crosses a ten, hundred or thousand — the problems where more than the last digit changes — wherever the range has that many; to 20 in ones there are only three. The page is titled by its step, so a sheet of tens reads 10 More, 10 Less.
1 token a sheet, fewer in batches.
US Letter PDF — prints on any home printer.
Read
The number in the middle of the row.
Step down
Write the number one less — or ten, or a hundred less — on the left.
Step up
Write the number that much more on the right.
More and less by
Numbers up to
Every number on the sheet stays inside the range — the answers too.
Crossing a ten, hundred or thousand
Crossings are the problems like 39 + 1 or 400 − 10, where more than the last digit changes. Lots is about half the page, where the range has that many.
Your worksheet lands here — download, print, or email it.