Three things can happen at the end of a Maths Challenge question: your child answers it and is right, answers it and is wrong, or leaves it blank. Which of those is sensible is not a fact about the competition. It is a fact about the paper in front of them, and it changed partway through the range of papers sitting in the practice room right now. That is the single most useful thing in this article, so it goes first.

Both competitions are the same shape: 25 multiple-choice questions, 60 minutes, no calculator, entered through school. Every paper in our bank — all twenty-four, Junior and Intermediate alike — is marked out of 135. The scoring is where they part company, and where the years part company from each other.

Which papers penalise a wrong answer

Paper Penalty for a wrong answer
IMC, every year 2015–2026 Yes — ten questions, 1 or 2 marks each
JMC 2020–2026 No — a wrong answer and a blank both score 0
JMC 2015–2019 Yes — ten questions, 1 or 2 marks each

A blank scores 0 on every paper in the bank. Never rewarded, never deducted.

UKMT dropped the penalty from the Junior Challenge in 2020. The older Junior papers are still in our practice bank — and they still score the old way, because that is how they were sat.

So the sentence a lot of guidance repeats, "the JMC doesn't penalise wrong answers", is true of a modern paper and false of a 2015–2019 one your child can sit in this room today. That matters more than it sounds, because of how children choose papers: a child working backwards through the year tiles, doing 2022, then 2021, then 2020, then 2019, crosses the boundary without anything announcing it. The room shows them the year. It does not put a klaxon on the change in scoring. This article is the klaxon.

What that means at the desk

On a paper with no penalty — a JMC from 2020 onwards. A blank is not protecting anything. It is a zero your child chose over a zero they might have been given, with a mark thrown away in the process. With a minute left and three empty boxes, filling them in is arithmetically free.

On a paper that penalises — any IMC, or a JMC from 2015 to 2019. The back ten questions flip the arithmetic. A blank there scores 0; a wrong guess there costs 1 or 2 marks. A blind guess is no longer a free shot, it is a bet, and losing it costs more than not having played.

On a penalising paper, then:

  • A genuine narrowing is still worth acting on. If your child has ruled options out with reasoning and is choosing between two, that is not a blind guess and it is a different proposition.
  • A blank is a legitimate answer. Leaving a question they have no purchase on is a defensible decision, not a surrender.
  • Time discipline matters more, not less. Minutes spent flailing at the back are minutes not spent checking the front — and here the flailing carries its own downside.
  • The front of the paper is unaffected. Only ten questions carry the penalty; on the rest, the no-penalty logic applies.

The practical habit to build is small: before the clock starts, know which paper this is. Junior or Intermediate: which one settles the competition; the year tile settles the rest.

How the practice room treats a blank

We built the room so a blank is a first-class thing to record, because a practice system that quietly punishes honesty will teach a child to guess and then hide it.

Sitting a paper under the clock. The All questions grid shows every question as answered, flagged or blank. Nothing scolds. When the hour runs out: "Time. Everything you chose was saved as you went. It's marked as it stands." Sitting a past paper under the clock walks through that.

Typing in a paper sat at school. The instruction is literally "Leave a blank blank." Twenty-five letters, or a dash where there was nothing. We would rather have the truth than a tidy grid — typing in a paper your child sat at school covers that door.

In a re-trap. When your child re-meets a trap a week later, a blank comes back with a line that is neither praise nor blame: "Left blank — honest, and it moves nothing." Both halves are doing work. Honest, because saying nothing beats faking something. Moves nothing, because a blank is not evidence the trap has been beaten. What a re-trap is explains why that distinction matters.

There is also an offered answer of "I'm not sure" in a re-trap. Not a wrong answer, not a blank — a third honest thing to say.

What happens to a guess that was wrong

This is the case parents ask about most, and the clinic handles it with some care.

Every wrong answer lands in the clinic filed under a named mistake rather than under the paper it came from. But not every wrong answer has a mistake behind it. Some are filed as no diagnosis: "Real wrong answers with no story — worth a look, nothing to fix by name."

The product's own explanation is worth quoting, because it is the same reason a guess belongs there: "Some wrong answers are just wrong. UKMT lays out plausible numbers on purpose, so this option doesn't point at a particular mistake."

A guessed letter carries no reasoning, so there is usually no misconception to name. Inventing one would be worse than useless — your child would be sent to fix a mistake they never made. When a wrong answer means nothing makes that case at length.

One honest caveat we show in the product itself: "Which mistake an option points to is our reading, not UKMT's." The naming is ours.

What to say to your child

  1. Check the paper, not the competition. Any IMC penalises. A JMC penalises if it is 2015 to 2019, and does not if it is 2020 or later.
  2. On a no-penalty paper, don't leave the last minute empty. Blanks are not protecting you.
  3. On the back ten of a penalising paper, a blank is a real option. Guess when you have narrowed it down with reasoning; think twice when you haven't.
  4. Record what actually happened. A guess entered as a guess is more useful to the clinic than a blank entered to look careful.

For background on the papers themselves, the audited guides to the Junior Challenge and the Intermediate Challenge cover format and entry.

FAQ

Does the Junior Maths Challenge penalise a wrong answer?

It depends on the year. JMC papers from 2020 onwards carry no penalty at all — a wrong answer and a blank both score 0. But JMC papers from 2015 to 2019 do penalise: ten questions per paper, 1 or 2 marks each. Those older papers are still in the practice bank, and they still score the old way.

What about the Intermediate Challenge?

Every IMC paper in the bank, 2015 through 2026, penalises a wrong answer on ten questions — the back ten — by 1 or 2 marks. There is no year of the IMC where a blind guess at the back of the paper is free.

Does the practice room treat a blank as a failure?

No. Leaving a question blank is a supported choice — when a child types in a paper they sat at school, the instruction is literally Leave a blank blank. In a re-trap a blank is reported honestly: Left blank — honest, and it moves nothing. A blank scores 0 on every paper in the bank: never rewarded, never deducted.

Duke Harewood built aitutors.me for his own KS3-aged daughter, who worked backwards through the year tiles one autumn and discovered the 2020 boundary the hard way. She has had opinions about blanks ever since. Updated 10 September 2026.