Page 22 - Maths Skills - 8

20 Maths

1 1 3
Example 7: Simran bought a pen set for ` 75 , a book for ` 250 and an umbrella for ` 125 from a
4 2 4
departmental store. How much money did she spend in all?

Solution: Cost of pen set = ` 75 1 , Cost of book = ` 250 1 , Cost of umbrella = ` 125 3
4
2
4
Thus, total cost = ` ( 1 1 3 301 501 503 301 1002 503+ +
75 4 + 250 2 + 125 4 ) = 4 + 2 + 4 = 4
903 1806
= = ` 451 1
4 2
2
Hence, the total expenditure is ` 451 1 .
2
−
−
11
3 − 4 + ( ) ( )
13
+
Example 8: Simplify: 2 5 15 10
−
−
4 11 13
13
Solution: 3 − 4 + ( ) ( ) = 3 − − −
11
+
2 5 15 10 2 5 15 10
= 45 24 22 39- - - = − 40 = − 4 =−1 1
30 30 3 3
Exercise 1.2

1. Add the following.

7 − 9 −15 3 8 10
(i) and (ii) and (iii) − and
13 15 7 19 9 3

11 6 4 19 − − 5 6
(iv) and (v) and (vi) and
17 23 37 105 19 57
2. Subtract the following.

3 1 − − 8 3 − −13 5
(i) from (ii) from (iii) from
5 9 22 55 14 7
19 7 7 2 5 13
(iv) from (v) from (vi) from
15 12 8 3 12 20
3. Verify the following.
( 2 − 3 ) − 7 2 ( − 3 − 7 ) 16 ( ) − 17 16
−
17
(i) 5 + 7 + 10 = 5 + 7 + 10 (ii) 19 + 21 = 21 + 19
(iii) ( −+ 1 ) ( ) =− +  1 + ( )   
−3
−3
+
8
8

4
17
17
 4
4. Find the product of.
13 2 27 6 34 16
(i) (ii)
9 7 26 17 9 21
3 4 121 26 51 125

(iii) (iv)
11 3 12 19 25 17