How do know when to add or subtract integers

It really depends on the sign in front of the numbers for that given example though -68-1 +(-6) you would have to add the -68 and -1 since they are both negative and then you would have to add it again to the -6 since they also have the same sign. Therefore the answer would be -75

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step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or