![Straw Scaffold](/sites/default/files/styles/medium/public/thumbnails/content-id-8847-icon.png?itok=_r3YFRa_)
Ratio and proportion
![Straw Scaffold](/sites/default/files/styles/medium/public/thumbnails/content-id-8847-icon.png?itok=_r3YFRa_)
![Toad in the Hole](/sites/default/files/styles/medium/public/thumbnails/content-id-8422-icon.png?itok=nILViLla)
problem
Toad in the Hole
Is it cheaper to cook a meal from scratch or to buy a ready meal? What difference does the number of people you're cooking for make?
![The Fastest Cyclist](/sites/default/files/styles/medium/public/thumbnails/content-id-8078-icon.png?itok=xdk-Dlmx)
problem
The Fastest Cyclist
Andy is desperate to reach John o'Groats first. Can you devise a winning race plan?
![Nutrition and Cycling](/sites/default/files/styles/medium/public/thumbnails/content-id-7571-icon.png?itok=7GvnTgar)
problem
Nutrition and Cycling
Andy wants to cycle from Land's End to John o'Groats. Will he be able to eat enough to keep him going?
![Triathlon and Fitness](/sites/default/files/styles/medium/public/thumbnails/content-id-7586-icon.png?itok=ZumBOT28)
problem
Triathlon and Fitness
The triathlon is a physically gruelling challenge. Can you work out which athlete burnt the most calories?
![Tray Bake](/sites/default/files/styles/medium/public/thumbnails/content-id-7781-icon.png?itok=SiOsTSuk)
problem
Tray Bake
My recipe is for 12 cakes - how do I change it if I want to make a different number of cakes?
![Placeholder: several colourful numbers](/themes/nrich/images/nrich_small_placeholder.png)
![Retiring to paradise](/sites/default/files/styles/medium/public/thumbnails/content-id-7722-icon.png?itok=uQLjQoNx)
problem
Retiring to paradise
When Charlie retires, he's looking forward to the quiet life, whereas Alison wants a busy and exciting retirement. Can you advise them on where they should go?
![Tennis Club](/sites/default/files/styles/medium/public/thumbnails/content-id-4738-icon.png?itok=XXHiixDz)
problem
Tennis Club
Three-quarters of the junior members of a tennis club are boys and the rest are girls. What is the ratio of boys to girls among these members?
![Speed-time problems at the Olympics](/sites/default/files/styles/medium/public/thumbnails/content-id-7322-icon.png?itok=A6u897LM)
problem
Speed-time problems at the Olympics
Have you ever wondered what it would be like to race against Usain Bolt?