💡 Hint
Read the wording closely: ‘from 25’ names a specific starting amount. Ask whether that amount is still what you are holding after your first try.
Reveal answer
Once. After the first subtraction you are working with 20, not 25.
Step-by-step solution
- Do the operation the question names: 25 – 5 = 20.
- The next subtraction would be 20 – 5. That is subtracting 5 from 20, not from 25.
- Every later step starts from an even smaller number (15, then 10, then 5), so none of them is “subtracting 5 from 25.”
- So you can subtract 5 from 25 exactly once. The tempting answer of 5 belongs to a different question: how many fives fit into 25.
Why it fools people
The puzzle swaps a reading task for a math task. The numbers 25 and 5 are a familiar pair from the multiplication table, so the brain runs 25 ÷ 5 before the sentence has been fully read. The words “from 25” get skipped because they look like setup rather than content. It’s a small, harmless version of a real and costly habit: solving the question you expected instead of the one on the page.
Did you get it?
About This Puzzle
Not every math puzzle is about computing. Some are about reading, and this one is the shortest test of reading we know. It fits on a single line, it uses two small numbers that everyone met in grade school, and it reliably catches adults who answer on autopilot. Children often get it right, partly because they read slowly and literally. Before you answer, give the question the same attention you would give a contract. Every word is there for a reason, and the short phrase at the end carries more weight than the numbers inside it.
How to Think About It
Separate what the question asks from what you expect it to ask. It does not ask how many fives fit into 25, and it does not ask how many steps it takes to reach zero. It asks about subtracting 5 from 25. So actually perform the operation once, on paper, and write down the result. Then look at the number in front of you and read the question again. Ask whether the next subtraction you would do still matches the words exactly. Literal, step-by-step reading is the whole method here, and it works on far harder problems too.
Common Traps
The tempting reply is a quick division. Your brain hears two numbers and a familiar operation, and it reaches for the multiplication table before the sentence is finished. A second trap is to decide the question is unfair and walk away. It isn’t unfair: it is precise, and the precise reading has one clear answer. If you started counting steps down toward zero, keep track of which number each step actually starts from, and compare it with the number named in the question.
Where This Puzzle Comes From
Questions like this belong to the long tradition of catch questions that teachers and puzzle books use to train careful reading. They sit next to old favorites such as “How many months have 28 days?” (all twelve do). Math contest coaches see the same habit cost points at every level, when students solve a slightly different problem from the one printed. Reading the question twice is worth more than any formula.
Try This Variation
Now a version where the steps really do repeat. Write down 25. Keep subtracting 5 and writing each result until you write 0. How many subtractions do you do, and how many numbers are on your paper in total, counting the 25 and the 0?
Show the answer to the variation
5 subtractions and 6 numbers: 25, 20, 15, 10, 5, 0. The two counts differ by one because each subtraction sits between two numbers, like fence sections between posts. Mixing up steps and stops is the famous fencepost error, another case of answering a nearby question instead of the real one.