Multiplication

Multiplication beyond the standard tables comes into view: anything times 0 is 0, and multiples of ten or a hundred can be handled by setting the zeros aside and falling back on the tables. Along with Multiplying by 0, Multiplying Tens and Hundreds (Mental Math), Fill in the Blank and Word Problems, products of three numbers show that the order of the work may be changed.

Writing 5 × 0 as 5, mixing it up with adding 0, shows up here. In multiples of ten the zero gets dropped, so 30 × 4 is answered as 12 and the result is one digit short. With three numbers, children compute the first pair and leave the last factor unused.

The way of using the times tables gained in Multiplication Word Problems in grade 2 is broadened here to include 0 and multiples of ten. Working forward through a table to find the answer is used again in the same form, run in reverse, when Division is studied later.