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If you are a student of class 8th and looking for an online mathematics mock test to evaluate your knowledge regarding this subject, you should try this simple quiz. It contains questions related to fractions, multiplications, and prime numbers. You can surely secure 100% marks on this test only if your basics are strong in Math. So, what else do you need? Get ready to test your understanding of mathematics. Best of luck to you.
Questions and Answers
1.
If 5^12 x 125 = 5^3x, find the value of x
A.
2
B.
4
C.
3
D.
5
Correct Answer D. 5
Explanation To find the value of x in the equation 5^12 x 125 = 5^3x, you can use the properties of exponents to equate the powers of 5 on both sides:
5^12 x 125 = 5^3x
First, simplify the left side:
5^12 x 125 = 5^12 x 5^3
Now, apply the rule for multiplying numbers with the same base when you have the same base raised to different exponents; you add the exponents:
5^(12 + 3) = 5^15
So, the equation becomes:
5^15 = 5^3x
Now that the bases are the same (both 5), you can equate the exponents:
15 = 3x
To solve for x, divide both sides by 3:
15 / 3 = x
x = 5
So, the value of x is 5.
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2.
6.37 x 10^{-4} in its usual form:
A.
63700
B.
6370000
C.
0.00637
D.
0.000637
Correct Answer D. 0.000637
Explanation The given number, 6.37 x 10-4, is in scientific notation. In scientific notation, a number is expressed as a decimal multiplied by a power of 10. In this case, 6.37 x 10-4 means that the decimal 6.37 is multiplied by 10 raised to the power of -4. To convert it to its usual form, we move the decimal point 4 places to the left, resulting in 0.000637. Therefore, the correct answer is 0.000637.
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3.
What is to be multiplied by (-15/16) to get 5/6 ?
A.
8/9
B.
-8/9
C.
-3/8
D.
3/8
Correct Answer B. -8/9
Explanation To find the number that needs to be multiplied by (-15/16) to get 5/6, we can set up a proportion. Let the unknown number be represented by x. So, (-15/16) * x = 5/6. To solve for x, we can cross-multiply and then divide both sides by (-15/16). This simplifies to x = (5/6) * (-16/15), which equals -8/9. Therefore, the correct answer is -8/9.
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4.
Which property is this 5/6 -+ 2/3 = 2/3 + 5/6
A.
Associative
B.
Commutative
C.
Distributive
D.
Closure
Correct Answer B. Commutative
Explanation The given equation 5/6 -+ 2/3 = 2/3 + 5/6 shows that the order of addition or subtraction does not affect the result. The terms 5/6 and 2/3 can be rearranged on either side of the equation, and the result will still be the same. This property is known as the commutative property of addition.
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5.
Which is bigger; -9/13 or -11/26
Correct Answer -11/26
Explanation The given question asks to compare -9/13 and -11/26. To compare fractions with different denominators, we need to find a common denominator. In this case, the common denominator is 26. When we convert -9/13 to have a denominator of 26, we get -18/26. Comparing -18/26 and -11/26, we can see that -11/26 is bigger because it has a smaller numerator. Therefore, the correct answer is -11/26.
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6.
50 times of 8 is equal to
A.
40
B.
4000
C.
8000
D.
400
Correct Answer D. 400
Explanation The correct answer is 400 because when you multiply 50 by 8, you get 400.
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7.
The missing terms in multiple of 3: 3, 6, 9, __, 15 is
Correct Answer 12
Explanation The missing terms in the sequence are multiples of 3. The given sequence starts with 3, then adds 3 each time to get the next term. Therefore, the missing term after 9 would be 12, as it is the next multiple of 3 in the sequence.
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8.
What is to be added to 5/4 to get 1?
Correct Answer -1/4
Explanation To find what needs to be added to 5/4 to get 1, we subtract 5/4 from 1. This can be done by finding a common denominator, which is 4 in this case. So, 1 can be written as 4/4. Subtracting 5/4 from 4/4 gives us -1/4. Therefore, -1/4 needs to be added to 5/4 to get 1.
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9.
Smallest prime number that is an even number too
A.
0
B.
1
C.
2
D.
3
Correct Answer C. 2
Explanation The smallest prime number is 2, and it is also an even number because it is divisible by 2.
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10.
The multiplicative identity of rational number is
A.
0
B.
1
C.
-1
D.
None of these
Correct Answer B. 1
Explanation The multiplicative identity of a rational number is the number that, when multiplied by any rational number, gives the same rational number as the result. In this case, the number 1 satisfies this condition. When any rational number is multiplied by 1, the result is always the same rational number. Therefore, the correct answer is 1.