Page 96 - Maths Class 06

3. Find:
(a) the successor of -100 (b) the predecessor of 0

(c) the negative of -50 (d) the additive inverse of 254
4. Fill in the blanks:
(a) - +6 c = 0 (b) -40 + 40 = c
(c) 15 + c = 0 (d) 0 + c = 0

5. Classify the following statements as true (T) or false (F):
(a) The sum of more than two integers cannot be zero. gg
(b) Every integer has both a predecessor and successor. gg
(c) The sum of two integers of the same sign is an integer of the same sign. gg

(d) The sum of the opposites of two integers equals the opposite of their sum. gg
(e) The sum of a positive integer a and a negative integer b is positive,
if a b> ; and negative if a b< . gg
6. Find the sum of -21, -9 63, , -22 and -28.

7. Add the successor of -99 and the predecessor of 9, and find the sum.
8. At 5 am, the temper a ture at a place was - °5 C. It rose by 7°C after three hours and stayed constant
for two hours. What were the temperatures at 8 am and at 9 am?
9. A diver is 10 m below sea level. His posi tion is given as -10 m. Give his new posi tion as inte ger, if he:
(a) goes down further by 10 m (b) comes up by 5 m.
10. In a Math quiz, 1 mark is gained for each correct answer. 1 mark is lost for each wrong answer.
There are 20 ques tions. If all ques tions are answered correctly, a student’s score will be 20; If all
questions are answered incorrectly, a student’s score will be -20.
Play ing the quiz, Suraj has a score of 4. What will be his score, if he:
(a) answers the next five questions correctly.

(b) answers the next five questions incorrectly.
(c) answers two of the next five questions correctly and three of them incorrectly.

Subtraction of Integers

We know that subtraction is the inverse of addition. For example, to subtract 4 from 9 is same as to find a
number which added to 4 gives 9.

i e. ., 9 - 4 = 5 Þ 4 5+ = 9
Let us use the number line. Move from 4 to 9 and count the number of steps.

–2 –1 0 1 2 3 4 5 6 7 8 9 10
Now let us subtract -3 from 7 which is 7 - -( 3). On the number line we count the number of steps in order
to reach 7 from -3. It is 10 steps to the left.

–4 –3 –2 –1 0 1 2 3 4 5 6 7 8 9
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