What Are They?

1. The product of two odd numbers is 99.

What are they?

2. The difference between two square numbers is 3.

What are they?

3. The sum of three prime numbers is 25.

What are they?

4. The ratio of two even numbers is 5:7.

What are they?

A Mathematics Lesson Starter Of The Day

Topics: Starter | Arithmetic | Number | Puzzles | Ratio

  • C. J. Southward, Limehouse Cumbria
  • In the product question the solutions do not include the double negative
  • Transum,
  • Thanks CJ. That has now been allowed for in the answers below.
  • 6N, Charnwood Primary School
  • We really enjoyed this and some of us thought it was easy - However we haven't tried the hard numbers yet!
  • Transum,
  • Click on one of the gold stars below and you will see a bar chart showing how people scored this starter. At the time of writing there were exactly the same number of votes for one as there were for five. This is probably because this starter requires a knowledge of some particular terms and concepts and some pupils will have this knowledge while others are too young to be expected to understand. Originally these starters were aimed at Secondary/High school pupils but they are commonly accessed by Primary school pupils, some only in Year 2!
    If you are one of the teachers who scored this page a one, have a look at some of the other starters as there is probably something that will suit your class. There are 366 Starters Of The Day with some additional Advanced Starters being added this month.

How did you use this starter? Can you suggest how teachers could present or develop this resource? Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for Maths teachers anywhere in the world.
Click here to enter your comments.

Previous Day | This starter is for 4 June | Next Day



1. 1 and 99 or 3 and 33 or 9 and 11 (and their negatives).

2. 1 and 4. Could there be any other solutions?

3. 3, 3 and 19 or 3, 5 and 17 or 3, 11 and 11 or 5, 7 and 13 or 7, 7 and 11.

4. 10 and 14 or 20 and 28 or 30 and 42 or ...


Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click a button below to regenerate another version of this starter from random numbers.

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Laptops In Lessons

Teacher, do your students have access to computers such as tablets, iPads or Laptops?  This page was really designed for projection on a whiteboard but if you really want the students to have access to it here is a concise URL for a version of this page without the comments:


However it would be better to assign one of the student interactive activities below.

Laptops In Lessons

Here is the URL which will take them to a related student activity.


Student Activity



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