Multiply and divide numbers by 10 and 100; understand this as equivalent to making a number 10 or 100 times the size, or 1 tenth or 1 hundredth times the size

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.

Multiplication is repeated addition of equal groups. Division shares a total into equal groups, or works out how many groups fit.

Number work here is about how our number system is built, and about knowing what a number is worth rather than just how it is spelled.