Watch three spinners on the board. On each one we work out the chance of a colour by counting the favourable segments (the ones we are asking about — here, the red ones) over the total segments. Then we write that same chance three ways: as a fraction, as a decimal, and as a percentage.

To turn a fraction into a decimal we divide the top number by the bottom number, then multiply by 100 to get the percentage:

• 1 ÷ 4 = 0.25
• 0.25 × 100 = 25%

So 1/4 = 0.25 = 25%. Look for how a fair spinner shares its chance equally, and be ready to say the third form for the last one before it appears.

Today we work through a fresh spinner together: an eight-segment spinner where three segments are prizes. We find the chance of a prize, then write it as a fraction, a decimal and a percentage.

This time the fraction does not land on a tidy landmark, so we divide the top by the bottom on the board, then multiply by 100 for the percentage.

Keep this reference table beside you as you work:

• 1/2 = 0.5 = 50%
• 1/4 = 0.25 = 25%
• 1/5 = 0.2 = 20%
• 1/8 = 0.125 = 12.5%

Then we spin it a few times so you can see the outcomes appear. Some of you will come up to set the spinner and read out the three forms.

• A 5-section spinner with 1 blue: chance of blue.
• A 10-section spinner with 3 red: chance of red.
• A 4-section spinner with 3 stars: chance of a star.
• An 8-section spinner with 1 winning slot: chance of a win.

For each one, set it up on the spinner, then write the chance as a fraction, a decimal and a percentage.