There are several stages of oral multiplication in the first volume of mathematics in grade three. First, multiply the whole ten by a number, such as 20×4. This kind of oral calculation regards the whole ten as several tens, and this number is multiplied. 20×4 means that 20 is regarded as two tens, and multiplying by 4 is eight tens, which is 80.

Second, a number is multiplied by an integer ten, such as 2×40. As above, the integer ten is also regarded as several tens, and then multiplied.

Triple multiplication is the multiplication of a single number. For example, 12×4 and 12 are the sum of 10 and 2. First use 10×2=20, then use 4×2=8, and then let 20+8=28.