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.
Let us see some example problems to understand the concept.
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.
After having gone through the stuff given above, we hope that the students would have understood "Adding and subtracting negative numbers".
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