Olympiad Test: Integers
20 Questions MCQ Test | Olympiad Test: Integers
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Two 'pluses' make a plus, two 'minuses' make a plus. A plus and a minus make a minus.
−4 × (7) = -28 [∵ (-) x (+) = (-)]
−45 ÷ 9 = −5
In this question, we have to multiply the integers with the same negative sign.
-5 x -6 = 30 [∵ (-) x (-) = +]
In multiplication, we have to multiply the sign of the integers also and then assign the obtained sign to the answer.
Negative sign multiplied by negative sign gives an overall positive sign.
LHS: (-8) + (-4) = -12
RHS: (-8) – (-4) = -4
⇒ -12 < -4 i.e. LHS<RHS
⇒ (- 8) + (- 4) < (- 8) – (- 4)
Thus, option C is correct.
The sum of two integers is -112. If one of them is -109 the other is:
Let other number be x.
⇒ x + (-109) = -112
⇒ x = -112 + 109 = -3
10 × (−3) = -30 [∵ (+) x (-) = -]
43 - (-17) = 60
-67 x (-1) = 67 [∵ (-) x (-) = +]
A place is 45 metre above sea level and another place is 25 meter below sea level. What is the difference of level in metres between the two places?
45 m above sea level = +45
25 m below sea level = -25
Therefore, 45 - (-25) = 70
-2 x (-1) = 2 [∵ (-) x (-) = +]
25 ÷ -5 = - 5 [∵ (+/-) = -]
At Shimla, temperature was -5°C on Monday and then it dropped by 2°C on Tuesday. What was the temperature of Shimla on Tuesday?
Temperature on Monday = -5°C
Temperature on Tuesday = Temperature on Monday - 2°C = -5°C - 2°C = -7°C
According to BODMAS,
6 × (−15 + 10) = 6 × (-5) = -30
[∵ -15 + 10 = -5]
(-1) × (-1) × (-1) × ......... (2m + 1) times, where m is a natural number, is equal to:
If negative terms are multiplied odd times, then the result will always be negative.
Thus option B is correct.
Manish deposits Rs 2000 in his bank account and withdraws Rs 1000 from it, the next day. Find the balance in Manish’s account after the withdrawal.
Manish deposits amount = 2000
Manish withdraws amount = -1000
Balance of Manish's account = 2000 + (-1000) = Rs 1000
Thus option C is correct.
According to BODMAS,
- (-2) × (3 + 5) = 2 x 8 = 16
When a positive integer and a negative integer are added, we may either get a negative integer or positive integer.
Example:
5 + (-2) = 3
2 + (-5) = -3
(−12 - 3) = -15
(− 6 + 3) = -3
⇒ (−12 - 3) ÷ (− 6 + 3) = (-15) ÷ (-3) = 5
If a = 20, b = 40 and c = 80 then a x b + a x c must be equal to
a = 20, b = 40, c = 80
According to BODMAS,
a x b + a x c = 20 x 40 + 20 x 80 = 800 + 1600 = 2400
-140 x 8 = -1120
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