Thinking of solving problems: Four arithmetic rules (calculation in sequence, first multiplication and division, then addition and subtraction, first parenthesis, first power), that is, disjoint operation (recursive equation calculation), should be carried out on the premise of this principle.

Problem solving process:

873-273+ 122

=600+ 122

=722

Extended data → vertical calculation-calculation process: align the units of the minuend and the minuend, and then subtract them from the numbers in the corresponding counting units respectively. If the drop is not enough, you need to borrow 1 from the high position and calculate it in turn to get the result. If the subtrahend is less than the minuend, the two numbers will be exchanged and then subtracted by the minus sign. Fractional subtraction can refer to the integer subtraction step;

Problem solving process:

Step 1: 3-3=0

Step 2: 7-7=0

Step 3: 8-2=6

According to the above calculation steps, the comprehensive calculation result is 600.

If in doubt, please ask questions. If satisfied, please adopt them.