Selina Concise Mathematics Class 6 ICSE Solutions – Negative Numbers and Integers
Selina Concise Mathematics Class 6 ICSE Solutions – Negative Numbers and Integers
EXERCISE 6
Fill in the blanks :
(i) Negative of -20 is ……….
(ii) Negative of 0 is …………
(iii) Negative of 8 is ………..
(iv) If 10 represents gain of ₹ 10, then -10 represents …………..
(v) If going south is negative then going north is …………
(vi) Because 5 < 7, therefore -5 ……….. -7. (vii) If 3 > -2, then 3 is on the ………….. of -2.
(viii) If -8 < -6, then -8 is on the …………. of-6.
Solution:
(i) 20
(ii) 0
(iii) -8
(iv) loss of ₹ 10
(v) positive
(vi) less than
(vii) right side
(viii) left side
Question 2.
Use a number line to write the following integers in ascending (increasing) order :
(i) -5, 8, 0, -9, 4, -14 and 12
(ii) -6, 7, 0, -9, 5 and 9
Solution:
(i) -5, 8, 0, -9, 4, -14 and 12
Draw a number line for integers,, as shown below, and mark on it all the given integers.
Clearly, the given integers in the ascending order are :
-14 < -9 < -5 < 0 < 4 < 8 < 12
(ii) -6, 7, 0, -9, 5 and 9
Draw a number line for integers, as shown below, and mark on it all the given integers.
Clearly, the given integers in the ascending order are :
-9 < -6 < 0 < 5 < 7 < 9
Question 3.
Use a number line to write the following integers in descending (decreasing) order :
(i) -10, 0, 3, -4, 12, 11, -1 and 5
(ii) -4, 3, -8, -12, -7 and 6.
Solution:
(i) -10, 0, 3,-4, 12, 11,-1 and 5
Draw a number line for integers, as shown below, and mark on it all the given integers.
Clearly, the given integers in the descending order are :
6 > 3 > 0 > -7 > -8 > -10 > – 12
(ii) -4, 3, -8, -12, -7 and 6.
Draw a number line for integers, as shown below, and mark on it all the given integers.
Clearly, the given integers in the descending order are :
6 > 3 > -4 > -7 > -8 > -12
Question 4.
Add:
(i) 13 and 15
(ii) -13 and 15
(iii) 13 and -15
(iv) -13 and -15
Solution:
(i) 13 and 15
13 + 15 = 28
(ii) -13 and 15
(-13) + 15 = 2
(iii) 13 and -15
= (13)+ (-15)
= 13 – 15 = -2
(iv) -13 and-15
= (-13) + (-15)
= -13 – 15 = -28
Question 5.
Add:
(i) 259 from 214
(ii) -528 and -243
(iii) -623 and 326
(iv) 258 and -473
(v) -622 and -254
(vi) 257 and -254
Solution:
(i) 259 from 214
= 259 + 214 = 473
(ii) -528 and-243
= -528 + (-243)
= -528 – 243
= -771
(iii) -623 and 326
= -623 + 326 = -297
(iv) 258 and —473
= 258 +(-473)
= 258 – 473
= -215
(v) -622 and-254
= -622 +(-254)
= -622 – 254
= -876
(vi) 257 and-254
= 257 +(-254)
= 257 – 254
= 3
Question 6.
Subtract :
(i) 5 from 8
(ii) -5 from 8
(iii) 4 from -7
(iv) -8 from -2
(v) -3 from 12
(vi) -6 from -3
Solution:
(i) 5 from 8
= 8 – 5 = 3
(ii) -5 from 8
= 8 – (-5)
= 8 + 5 = 13
(ii) 4 from -7
= -7 – 4
= -11
(iv) -8 from -2 = -2 – (-8)
= -2 + 8
= 6
(v) -3 from 12
= -12 – 3 = -15
(vi) -6 from -3
= -3 – 3 (-6)
= – 3 + 6 = + 3
Question 7.
Subtract:
(i) -123 from 453
(ii) -78 from -12
(iii) 329 and -124
(iv) -222 from 0
Solution:
(i) -123 from 453
= + 453 – (-123)
= 453 + 123 = 576
(ii) -78 from -12
= -12 – (-78)
= -12 + 78 = 66
(iii) 329 and-124
= + 329 – 124 = 205
(iv) -222 from 0
= 0 – (-222)
= 0 + 222 = 222
Question 8.
Using a number line, find the integer which is :
(i) 3 more than -1
(ii) 5 less than 2
(iii) 5 more than -9
(iv) 4 less than -4
(v) 7 more than 0
(vi) 7 less than -8
Solution:
