Conversion Columns

Explore converting lengths, mass and capacity

Models:

Slide the units (the default): the decimal point and the place value columns stay still. The strip of units slides, carrying its digits with it, until the unit you want sits over the yellow ones column. Each digit stays with its unit, so the length never changes, and each digit moves left (bigger) or right (smaller) past the fixed point.

French chart: the French tableau de conversion. The digits stay still and the decimal mark is placed after the unit you want.

Instructions (Slide the units):

1. Drag digits from the tray onto the strip, one digit per column. Put the units digit in the column over the yellow ones column.
2. Tap the unit you want. The strip slides until that unit is over the ones column.
3. When the strip stops, blue covers hide every digit of the answer. Ask the class what goes under each one, then tap it to reveal the digit. Watch for the places that need a zero to hold them. The answer appears when every cover is off, or tap the ? in the answer to reveal them all.
4. The line under the answer links the slide to multiplying or dividing, for example "1 m = 100 cm, so each digit moves 2 places to the left: × 100".
5. Pale zeros are not needed and can be left out, for example the zeros in 25.00 m.

Instructions (French chart):

1. Drag digits from the tray onto the chart, one digit per column. Put the units digit in the column of the unit you were given.
2. Drag the decimal mark onto a column to place it after that column.
3. Tap the header of the unit you want. Empty columns fill with zeros and the decimal mark moves to just after that column.

In either mode, drag a digit off the chart to remove it, or press Clear to start again. Switching mode keeps the number on the board. Choose Length, Capacity or Mass at the top to work in metres, litres or grams: the columns work in exactly the same way for each. Choose English, Français or Deutsch to change the decimal mark, the place value labels and the unit names.

Have fun!