Capacity Countdown is a tablet-friendly volume scale
Y1:To begin to measure capacity and volume [for example, full/empty, more than, less than, half, half full, quarter].
Y1:To measure and begin to record capacity and volume.
Y2:To choose and use appropriate standard units to estimate and measure length/height in any direction (m/cm); mass (kg/g)
temperature (°C); capacity (litres/ml) to the nearest appropriate unit, using rulers, scales, thermometers and measuring vessels.
Y3:To measure, compare, add and subtract: lengths (m/cm/mm); mass (kg/g); volume/capacity (l/ml).
Press the green arrow button.
Read the scales to find the volume of the rocket fuel.
Type the volume on the keypad.
Press 'check' - if you're correct the rocket will launch.
Make it trickier, you can enter half a litre as ½ l or 500 ml.