Here is a pancake recipe that feeds four people: 2 eggs, 400 g of flour and 600 ml of milk. Tonight, eight people are coming for pancakes.

How would you change the recipe so everyone gets the same-sized pancakes? What has to happen to every ingredient?

The interactive shows four recipes as ratio bars, where each bar's length is that ingredient's share. Look at the four recipes shown as ratio bars. For each recipe, say what the bars show and how the amounts relate before we agree it as a class.

Today we'll build this on the ratio bars together. Here is a new smoothie: 1 part banana to 5 parts milk, poured into a 900 ml jug for a group. Before we reveal it, tell me how many equal parts share the 900 ml and what one part is worth. Then we'll set the bars and read off each actual amount.

Today we'll work through three mixtures together, each one a little harder than the last. Tell me how many parts share the total before we reveal each one.

• Make a 1:2 lemon-and-water drink in a 900 ml jug.
• Make 700 g of a nut-and-raisin mix. It starts as 250 g nuts to 100 g raisins — divide both by 50 to get 5 parts nuts to 2 parts raisins.
• Make a 2:3 blue-to-white paint mix in 2500 ml.