Easy Algebra Step-by-Step

18 Easy Algebra Step-by-Step

Rule 2. To add two numbers that have

opposite signs, subtract the lesser

absolute value from the greater abso-

lute value and give the sum the sign of

the number with the greater absolute

value; if the two numbers have the

same absolute value, their sum is 0.

Rule 3. The sum of 0 and any number is

the number.

Problem Find the sum.

a. −+ 35 − 60

b. 35 +− 60

c. −+ 35 60

d. −+^2

9

7

9

e.

2

9

7

9

+−

f. − 975858 ++−. 12

g. −+ 99036 0

Solution

a. −+ 35 − 60

Step 1. Determine which addition rule applies.

−+ 35 − 60

The signs are the same (both negative), so use Rule 1.

Step 2. Add the absolute values, 35 and 60.

35 += 6060 95

Step 3. Give the sum a negative sign (the common sign).

−+ 35 −= 60 − 95

b. 35 +− 60

Step 1. Determine which addition rule applies.

35 +− 60

The signs are opposites (one positive and one negative), so use Rule 2.

These rules might sound

complicated, but practice will make

them your own. One helpful hint is

that when you need the absolute

value of a number, just use the

value of the number with no sign

attached.