Know that 10 hundreds are equivalent to 1 thousand, and that 1,000 is 10 times the size of 100; apply this to identify and work out how many 100s there are in other four-digit multiples of 100

What this means, in plain words

Two fractions are equivalent when they are worth the same amount even though the numbers look different, such as one half and two quarters.

A multiple of a number is what you get when you multiply it by a whole number, so 12 is a multiple of 3.

A digit is one of the ten symbols, 0 to 9, that all numbers are written with.