Important Questions: Exponents and Powers
20 Questions MCQ Test Mathematics (Maths) Class 7 | Important Questions: Exponents and Powers
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We have
23+23+23+23 = 4 × (23)
= 22 × 23 = 25
is ____.
= 0
{(1/3)−3−(1/2)−3} ÷ (1/4)−3 = {(3)3−(2)3} ÷ (4)3 = {27−8} ÷ 64 = 19/64
The value of (−8) × (−8) × (−8) × (−8) × (−8) + (−8) × (−8) × (−8) × (−8) × (−8) is ____.
(−8)5+ (−8)5 = −2×(8)5 = −2×(2)15
= −(2)16 = −(4)8
If (5/3)−5 × (5/3)11 = (5/3)8+x, then x = ?
(5/3)−5 × (5/3)11 = (5/3)8+x
⇒ (5/3)−5+11 = (53)8+x
⇒ (5/3)6 = (5/3)8+
On comparing, we get,
8 + x = 6
⇒ x = −2
=(a−2+3 × b−3+4)
= a×b
= ab
{(3/4)−1−(1/4)−1}−1 = {4/3−4}−1 = {−8/3}−1=−3/8
Express the given number using exponential notation: 3125
3125 = 5 × 5 × 5 × 5 × 5 = 55
If (5/9)4 × (5/9)−10 = (5/9)−4(5/9)2a−1,then the value of a is _____.
Equating the powers,
-6=2a-5
2a=-1
a=-1/2
Which of the following is equivalent to 7.7×10−6 ?
7.7×10−6 = 7.7/100000 = 0.0000077
If (3/2)2 × (3/2)a+5 = (3/2)8, then a = ____.
(3/2)2 × (3/2)a+5 = (3/2)8
⇒(3/2)a+7 = (3/2)8
On comparing, we get,
a+7 = 8 ⇒ a =1
The number which is multiplied by (−8)−1 to obtain a product equal to 10−1 is ____.
Let the number be x, Then, (−8)−1× x = (10)−1
⇒(−1/8) × x = (1/10) ⇒ x= −4/5
Correct Answer :- b
Explanation : [(2*3)12 * (5*7)28 * (5*3)16]/[(7*2)12 * (7*3)11 * 528]
= [(2)12 * (3)12 * (5)28 * (7)28 * (5)16 * (3)16]/[(7)12 * (2)12 * (7)11 * (3)11 * (5)28]
= [(2)12 * (3)12+16 * (5)28+16 * 316]/[(7)12+11 * (2)12 * (3)11 * (5)28]
= [(2)12 * (3)28 * (5)44 * 316]/[(7)23 * (2)12 * (3)11 * (5)28]
= 317 * 516 * 75
The value of ab − ba, if a = 3, b = 7 is
ab − ba =37−73 = 2187−343 = 1844
The value of (23/25)0 × (−1/2)5 ×23 × (3/4)2 is
(23/25)0 × (−1/2)5 ×23 × (3/4)2
=1×(−1)5 × (2)−5 × 23 × 32 × (2)−4=−9/64
A rectangular piece of land is to be sold off in smaller pieces. The total area of the land is 217 sq. miles. The pieces to the cut out are 162 sq. miles in size. How many smaller pieces of the land can be sold at the given size?
Required number of pieces
Pooja spends about Rs.40000 each month on utensils hold. If she has about 1×108 utensils, what is the total amount of money (in Rs.) spent on the households in one month?
Total amount of money spent Rs.(40000×1×108) = Rs.(4.0×1012)
All the planets revolve around the Sun in elliptical orbits. Uranus's farthest distance from the Sun is approximately 3.004×109 km and its closest distance is approximately 2.7499×109 kmkm. What is the average distance of Uranus from the Sun?
Distance of Uranus from Sun =(3.004×109)km
Uranus closest distance from Sun =(2.7499×109)km
Total distance = 3.004×109 + 2.7499×109
= (5.753×109)km
Average distance = (5.753×109)/2
= (2.8765×109)km
There are three places A, B, C in a straight line as shown below. If distance between place A and B is (2.4×106)m and distance between 8 and C is (5.2×105)m, then find the distance between place A and C in standard form. 
Distance between place A and B
= 2.4×106m = 2400000 m
Distance between place 6 and C = 5.2×105 m = 5.2×100000 m = 520000 m
Distance between place A and C
= (2.4×106 + 5.2×105)m = (2400000 + 520000)m = 292×104m
Standard form of 292×104m = 2.92×106
Mr Gupta asked two of his students to solve the expression 
and write the answer on blackboard. Aryan wrote the answer as 3a−4b5 whereas Ayan wrote the answer as 
. Who wrote the correct answer?
We have,
= 3a−4b5
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