Page 97 - Maths Class 06

Therefore, 7 - -( 3 =) 10
Numerically, subtraction means adding the additive inverse.
NOTE
To subtract an integer b from integer a, we add the opposite of b to
a , i e. . to subtract an integer add its opposite. Thus, every Negative of a negative integer is
subtraction problem may be regarded as an addition problem. the corresponding positive integer.
EXAMPLE 1. Subtract:
(a) 10 from 7 (b) -8 from 3

(c) 3 from -6 (d) -4 from -8
SOLUTION : (a) 7 10- = 7 + -( 10) (Adding opposite of 10)
= -3
(b) 3 - -( 8 = + +) 3 ( 8) (Adding opposite of -8)
= +11

(c) (-6 ) ( ) (- 3 = -6 ) (+ -3 (Adding opposite of 3)
)
= -9
)
(d) (-8 ) (- -4 ) (= -8 ) (+ +4 (Adding opposite of -4)
= -4
EXAMPLE 2. Subtract:
(a) -124 from 317 (b) -1140 from -2130

(c) 319 from -125 (d) -317 from -815
SOLUTION : (a) 317 - -( 124) = 317 + +124( ) (Adding opposite of -124)
= + 441
)
)
(b) (-2130 ) (- -1140 = -( 2130 ) + +( 1140 (Adding opposite of -1140)
= -990
(c) (-125 ) (- 319 ) (= -125 ) (+ -319 (Adding opposite of 319)
)
= -444
)
(d) (-815 ) (- -317 ) (= -815 ) (+ +317 (Adding opposite of -317)
= -498
To simplify an expression containing more than two terms with + and - signs, we follow the procedure
given below:

Step 1. Add all terms with + sign.
Step 2. Add the terms with - sign.

Step 3. Find the difference of the absolute value of the two sums obtained in Step 1 and 2.
Step 4. Assign to the difference obtained in Step 3, the sign of the sum having greater absolute value.
EXAMPLE 3. Simplify: (-10 ) (+ -70 ) (- -80 ) (+ -6 )

SOLUTION : We rewrite the expression as:
-10 -70 + 80 - = -6 ( 10 -70 6) + 80 [Q- (-80 ) = +80 ]
-
= -86 + 80

= -6

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