Page 99 - Maths Class 06

8. Fill in the blanks:
(a) - +3 (…) = -12 (b) 13 + -( 13 =) (…) (c) - +6 (…) = 0 (d) 11- (…) = 22

9. Calculate the sum:
3 + -( 3 + +) 3 ( 3 + + -) 3 ( 3 +) ……
(a) If the number of terms is 40. (b) If the number of terms is 71.
10. Which of the following statements are true?

(a) - + -4 ( 2) < 2 (b) -13 > - - -8 ( 2) (c) -16 + -16( ) = 0
(d) The negative of a negative integer is a negative integer.
11. The sum of two integers is -50. If one of them is 78, what is the other integer?

12. Two cars started from the same point. First car went towords the east and covered 64 km in one
hour. The second car went towards the west and covered 58 km in one hour. Find the distance
between the two cars after one hour.

At a Glance

l The collection of numbers …, -4, -3, -2, -1 , 0, 1, 2, 3, 4, … is called integers.
l -1 , -2, -3, -4, … are called negative integers; and 1, 2, 3, 4, … are called positive integers.

l 0 is neither a positive nor a negative integer. It is simply called an integer.
l Every integer has a successor as well as a predecessor.

l Integers can be represented on a number line.
l With the help of a number line, we can (a) compare (b) add (c) subtract, any two integers.
l A positive integer is greater than zero and also every negative integer.

l A negative integer is less than zero and also every positive integer.
l Rule for Addition of integers:

1. When two positive integers are added, the sum is a positive integer.
2. When two negative integers are added, the sum is a negative integer.
3. When two integers of different signs are added, we find their difference and prefix the sign of the
integer having greater numerical value.

l If a and b are any two integers, then
a b a- = + -( b) [where -b is the additive inverse of b]

Multiple Choice Questions

Tick (3) the correct answer:
1. Successor of – 13 is:
(a) -14 (b) -12 (c) 0 (d) 15

2. The additive inverse of – 3 is:
(a) 0 (b) 2 (c) 3 (d) –3

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