We have been matching fractions, decimals and percents — the same amount written three ways. Some of these are easy to read straight off as tenths or hundredths; a few are trickier. Now look at this new value: 1/8. Have a guess: what is 1/8 as a decimal? What about as a percentage? Don't worry if you are unsure — we will check it together in a moment.

The interactive shows four fractions, each one as a fraction, a decimal and a percentage, using a phone battery. Watch how full each battery gets, and notice which decimals stop cleanly and which run on forever.

Now we work through these values together on the board: 3/5, then 1/4, then 9/10, and finally 1/6. We will all predict the decimal and percent first, then a named pupil comes up to drag the battery slider and check. Three of them stop cleanly, and one is a new one that runs on. Say which is which before we check each one.