Measurement and Data

Changing between units of measure

Change a measurement from a larger unit to a smaller one and back again, and add measurements written in mixed units.

The same length can be written in more than one way. A ribbon does not change when you call it 2 feet instead of 200 inches — only the words change, and the number changes with them. Measuring in a smaller unit always needs a bigger number, because it takes more small things to cover the same distance.

The three facts worth knowing by heart

There are 100 inches in 1 feet, 1,000 feet in 1 miles, and 1,000 oz in 1 lb. Everything else in this skill is one of those three facts plus a multiplication or a division: larger unit to smaller, multiply; smaller unit to larger, divide.

Worked example

How many inches are there in 4 feet?

  1. One feet is 100 inches.

    That is the fact everything else hangs off.

Try it together

Now let us turn 2 feet and 35 inches into a single number together.

A measurement written in two units has to be brought into one unit before it can be added up.

    1.First change the larger part across. How many inches are 2 feet?

    Have a go

    Have a go on your own. There are 1,000 oz in 1 lb. How many oz are there in 6 lb? Give just the number.

    Hint: Six lots of a thousand.

    Ready to practice?

    Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.

    Print a worksheet