ADDING AND SUBTRACTING NEGATIVE NUMBERS

Whenever we want to simplify two numbers, first we have to check if numbers are having same sign or different sign.

• If both numbers are having same signs, then add both numbers and tag greater number sign for the answer.
• If both numbers are having different signs, then subtract the smaller number from the greater number and tag the greater number sign for the answer.

Example 1 :

Simplify (–10) + (+17)

Solution :

  =  –10 + 17

By considering the above numbers, both are having different signs. So,

Subtract the smaller number from greater number and tag greater number sign.

  = +7

Hence, 7 is the answer.

Example 2 :

Simplify  (+20) + (–13)

Solution :

  =   (+20) + (–13)

=   +20 –13

By considering the above numbers, both are having different signs.

Subtract the smaller number from greater number and tag greater number sign.

  = +7

Hence, 7 is the answer.

Example 3 :

Simplify  (–50) + (–20)

Solution :

  =   (–50) + (–20)

=   –50 – 20

By considering the above numbers, both are having same signs.

Add both numbers and tag greater number sign.

  = -70

Hence, -70 is the answer.

Example 4 :

Simplify  (+40) + (+70)

Solution :

  =   (+40) + (+70)

=  + 40 + 70

By considering the above numbers, both are having same signs.

Add both numbers and put greater number sign.

  = + 110

Hence, 110 is the answer.

Example 5 :

Simplify  (+18) + (–75)

Solution :

  =   (+18) + (–75)

=  +18 –75

By considering the above numbers, both are having different signs.

Subtract the smaller number from greater number, put greater number sign.

  = - 57

Hence, -57 is the answer.

Example 6 :

Simplify   (+75) + (–75)

Solution :

  =    (+75) + (–75)

=  + 75 – 75

By considering the above numbers, both are having different signs.

Subtract the smaller number from greater number, put greater number sign.

  = 0

Hence, 0 is the answer.

Example 7 :

Simplify   (–30) + (12)

Solution :

  =   (–30) + (12)

=   –30 + 12

By considering the above numbers, both are having different signs.

Subtract the smaller number from greater number, put greater number sign.

  = -18

Hence, -18 is the answer.

Example 8 :

Simplify   (–30) + (–22)

Solution :

  =   (–30) + (–22)

=   –30 – 22

By considering the above numbers, both are having same signs.

Add both numbers and put greater number sign.

  = - 52

Hence, -52 is the answer.

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