99 divided by 20 equals 4, leaving 19.
When checking, first calculate 20 times 4, and the vertical expression is as follows:
Then calculate 80+ 19, and the vertical expression is as follows:
After the result of the topic is calculated, it is calculated once by inverse operation (such as addition for subtraction and multiplication for division) to check whether the result of the previous operation is correct.
Extended data:
Vertical calculation of multiple digits multiplied by one digit
1, aligned with the same number.
2. Multiply this number by the number on each of multiple numbers, starting with a single number, that is, from right to left.
When you multiply the product by which number, write the product under the corresponding number.
4. If you want to carry, the product of which bit is more than dozens, just move forward a few times and then continue to multiply down.
In multiplication:
"×" is a multiplication sign, the numbers before and after the multiplication sign are called factors, "=" is an equal sign, and the numbers after the equal sign are called products.
10 (factor) × (multiplication sign) 200 (factor) = (equal to sign) 2000 (product) factor is also called multiplier.