Methods One-digit multiplication, two-digit multiplication and multi-digit multiplication are divided, and one-digit multiplication is directly calculated by multiplication formula.

Multiply one digit by multiple digits, and the multiplicand exceeds three digits or three digits, and calculate vertically.

Multiplication arranges two numbers vertically and writes them up and down, so that the two numbers are aligned to the right. Write the multiplication sign at the far left of the low digit, write the horizontal line below the low digit, and then calculate.