Calculate the formula according to the meaning of the question:
8-3+ 1
=5+ 1
=6
So * * * have a holiday for six days.
Arithmetic operation of addition and subtraction:
Integer addition and subtraction, the same digits are aligned, starting with single digits, and when the addition reaches ten digits, the higher digits will be entered; If the subtraction is not enough, subtract 1 from the high position. When this number is added to 10, it will decrease.
If you subtract several numbers from a number in succession, you can add all the subtractions first, and then subtract the sum of the subtractions from the minuend. For example: 276-115-85 = 276-(115+85) = 76.