the rol
DAI
1. 24 - 3 x 15 + 5
simplifier
4. (3 * 7 + 18) + (2 + 13) - 4
Answers
Answer:
Step-by-step explanation:
Question 1:
Carry out the following additions of rational numbers.
(i)
5
36
+
6
42
(ii) 1
2
3
+2
4
5
(iii)
11
17
+
13
19
(iv) 2
3
11
+1
3
77
ANSWER:
(i)
5
36
+
6
42
At first, we will calculate the LCM of 36 and 42. The prime factorisation is 36 and 42 is,
36 = 2 × 2 × 3 × 3
42 = 2 × 3 × 7
Now, LCM of 36 and 42 = 2 × 2 × 3 × 3 × 7 = 252
5
36
+
6
42
=
5×7
36×7
+
6×6
42×6
=
35
252
+
36
252
=
35+36
252
=
71
252
(ii) 1
2
3
+2
4
5
=
1×3+2
3
+
2×5+4
5
=
5
3
+
14
5
Now, LCM of 3 and 5 is 15.
5
3
+
14
5
=
5×5
3×5
+
14×3
5×3
=
25
15
+
42
15
=
67
15
=4
7
15
(iii)
11
17
+
13
19
Now, LCM of 17 and 19 is 323.
11
17
+
13
19
=
11×19
17×19
+
13×17
19×17
=
209
323
+
221
323
=
430
323
(iv) 2
3
11
+1
3
77
=
2×11+3
11
+
1×77+3
77
=
25
11
+
80
77
Now, LCM of 11 and 77 is 77.
25
11
+
80
77
=
25×7
11×7
+
80×1
77×1
=
175
77
+
80
77
=
255
77
=3
24
77
Page No 36:
Question 2:
Carry out the following subtarctions involving rational numbers.
(i)
7
11
-
3
7
(ii)
13
36
-
2
40
(iii) 1
2
3
-3
5
6
(iv) 4
1
2
-3
1
3
ANSWER:
(i)
7
11
-
3
7
Now, LCM of 11 and 7 is 77.
7
11
-
3
7
=
7×7
11×7
-
3×11
7×11
=
49
77
-
33
77
=
49-33
77
=
16
77
(ii)
13
36
-
2
40
Now, LCM of 36 and 40 is 360.
13
36
-
2
40
=
13×10
36×10
-
2×9
40×9
=
130
360
-
18
360
=
130-18
360
=
112
360
=
112÷8
360÷8
(since, HCF of 112 and 360 is 8)=
14
45
(iii) 1
2
3
-3
5
6
=
1×3+2
3
-
3×6+5
6
=
5
3
-
23
6
Now, LCM of 3 and 6 is 6.
5
3
-
23
6
=
5×2
3×2
-
23×1
6×1
=
10
6
-
23
6
=
10-23
6
=-
13
6
(iv) 4
1
2
-3
1
3
=
4×2+1
2
-
3×3+1
3
=
9
2
-
10
3
Now, LCM of 2 and 3 is 6.
9
2
-
10
3
=
9×3
2×3
-
10×2
3×2
=
18
6
-
20
6
=
18-20
6
=-
2
6
=-
1
3
Answer:
21·h38-+1587+556446664566