How to calculate the number of times of multiplication and addition if the X item is missing or other items are missing in the compulsory three Qin and nine Shao algorithm of mathematics published by People's Education Press? The coefficient of missing items is 0, x 4+2x 3+0x 2+5x.

Then we use the original method to get: (((x+2) x+0) x+5) x.

Then ignore 0, that is, ((x+2)x times x+5) x.

Counting is two additions and two multiplications.