The answer process is as follows:

Assuming all the answers are correct, the score should be 20×5= 100 (points);

But the actual score: 100-82= 18 (points);

There are fewer questions than incorrect answers: 5+ 1=6 (points);

Incorrect answer: 18÷(5+ 1)=3 (Dao);

Correct answer: 20-3= 17 (Dao);

A: He answered 17 correctly.

Extended data

The multiplication rule of integers is one of the arithmetic rules of integers. The multiplication rule of integers is manifested in three situations:

1 and the multiplication rule of one digit. The product of two one-digit numbers can be calculated by addition according to the definition of multiplication. Usually, the product of any two one-digit numbers can be directly obtained by using the multiplication table.

2. Multi-digit multiplication rule. Multiply the number on each bit of the multiplicand by the number on each bit of the multiplier in turn, and then add the products.

3. For any number A, a× 1=a, a×0=0×a=0.

Integer addition is one of the basic addition operations. Addition, that is, du, combines more than two integers into one number, and the result is called sum. The addition symbol is the plus sign (+). Connect items with a plus sign when adding. Put and after the equal sign (=). Example: If the sum of 1, 2 and 4 is 7, it is written as 1+2+4=7.