Easy Algebra Step-by-Step

Computation with Real Numbers 21

You subtract signed numbers by changing the subtraction problem to an

addition problem in a special way, so that you can apply the rules for addi-

tion of signed numbers. Here is the rule.

Subtraction of Signed Numbers

Rule 4. To subtract two numbers, keep the fi rst number and add the

opposite of the second number.

To apply this rule, think of the minus sign, −, as “add the opposite of.” In

other words, “subtracting a number” and “adding the opposite of the num-

ber” give the same answer.

Problem Change the subtraction problem to an addition problem.

a. −− 35 60

b. 35 − 60

c. 60 − 35

d. −−^35 ()−^60

e. 060

f. −− 60 0

Solution

a. −− 35 60

Step 1. Keep − 35.

− 35

Step 2. Add the opposite of 60.

=− 35 +− 60

b. 35 − 60

Step 1. Keep 35.

35

Step 2. Add the opposite of 60.

=+ 35 − 60

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