Mathematics Indices Questions and Answers for WAEC, NECO, JAMB, GCE, Post-UTME and NABTEB
- WAEC
- NECO
- JAMB
- GCE
- Post-UTME
- NABTEB
Understanding the Laws of Indices
•
Multiply, same base, add the
powers:
•
Divide, same base, subtract
the powers:
•
Power of a power, multiply
the powers:
•
Power zero:
•
Negative power, flip the
number:
•
Fractional power: and
•
Same base on both sides: if , then
•
Difference of two squares:
•
Standard form: , where
is
at least 1 but less than 10
•
Significant figures (s.f.): start counting from the first non-zero digit. Look at the next
digit: if it is 5 or more, round up; if it is 4 or less, leave the last digit
as it is.
•
Sum of odd numbers: (the
first
odd
numbers)
MATHEMATICS INDICES OBJECTIVE QUESTIONS AND ANSWERS
Question 1
If , find
. [2009
Q31]
Options: A. 2 B. 1 C. D.
Step 1: Change everything to base 3. ,
and
.
Step 2: Same base, so equate the powers.
Answer: C.
Question 2
Simplify
Options: A. 16 B. 8 C. 4 D. 1
[2014 Q35]
Step 1: Change everything
to base 2. ,
and
.
Step 2: Top and bottom.
Step 3: Divide (subtract the powers).
Step 4: Take the square
root.
Answer: C.
Question 3
If , find the value of
.
Options: A. 1 B. C.
D.
[2015 Q4]
Step 1: Change to base 3. and
.
Step 2: Write 1 as a power
of 3. , so
Answer: B.
Question 4
If , find
Options: A. B.
C.
D.
[2015 Q7]
Step 1: Split the power (adding powers means multiplying).
Step 2: Rewrite using
.
Step 3: Put it together.
Answer: A.
Question 5
Given that , find
.
Options: A. B.
C.
D.
[2010 Q18]
Step 1: Change 25 to base
5. , so
.
Step 2: Divide (subtract the powers).
Step 3: Equate the powers. The right side is .
Answer: C.
Question 6
Simplify
Options: A. B.
C.
D.
[2008 Q10]
Step 1: Take the cube root
of each part separately.
Step 2: Multiply them
together.
Answer: C.
Question 7
Simplify
Options: A. B. 9 C.
D.
[2016 Q7]
Step 1: Change to base 3. and
.
Step 2: Top.
Step 3: Divide.
Answer: B.
Question 8
If , find the value of
Options: A. B.
C.
D.
[2008 Q30]
Step 1: Find .
, so
.
Step 2: Put into the
expression.
Step 3: Split as
, so we can pair the 2s with the 5s.
Answer: B. . Option D reads the same in the scan, so one of
them is probably a misprint.
Question 9
Simplify
Options: A. 1 B. C.
D.
[2007 Q7]
Step 1: Expand the bottom. Everything inside the bracket gets the power 3.
Step 2: Divide. The cancels.
Answer: C.
Question 10
If , find
.
Options: A. B.
C.
D.
[2007 Q13]
Step 1: Change to base 2. and
.
Step 2: Equate the powers
and solve.
Answer: D.
Question 11
If , find the value of
.
Options: A. B.
C.
D. 3 [2011
Q46]
Step 1: Change to base 3.
Step 2: Equate the powers.
Step 3: Divide both sides
by to get
.
Answer: B.
Question 12
If , find the value of
.
Options: A. 1 B. 2 C. 3 D. 4
[2009 Q13]
Step 1: Take the cube root
of both sides. .
Step 2: Solve.
Answer: A.
Question 13
If , find
.
Options: A. 1 B. C. 2 D.
[2013 Q2]
Step 1: Change to base 3.
Step 2: Equate the powers
and solve.
Answer: B.
Question 14
Given that , find
in terms
of
.
Options: A. B.
C.
D.
[2017 Q43]
Step 1: Find in
terms of
. A negative power
means “flip”.
Step 2: Split .
Answer: A.
Question 15
Solve:
Options: A. B.
C.
D.
[2012
Q39]
Step 1: First part. Flip the fraction to remove the negative sign, then take the cube
root.
Step 2: Second part. The power means
square root.
Step 3: Multiply.
Answer: A.
Question 16
If and
, calculate
Options: A. B. 1 C.
D.
[2013
Q11]
Step 1: Work out each
power.
Step 2: Top and bottom.
Answer: C.
Question 17
Simplify and
express your answer in standard form.
Options: A. B.
C.
D.
[2010 Q1]
Step 1: Write each number
in standard form.
Step 2: Multiply the
numbers, then the powers of 10.
Answer: D.
Question 18
Evaluate
Options: A. B.
C.
D.
[2008 Q2]
Step 1: Use the difference
of two squares on the top.
Step 2: Cancel the common bracket .
Answer: B.
Question 19
Find the product of 0.0403
and 0.0021, leaving your answer in standard form.
Options: A. B.
C.
D.
[2008 Q3]
Step 1: Write each number
in standard form.
Step 2: Multiply the
numbers, then the powers of 10.
Step 3: Combine. , which is
to 3 s.f.
Answer: B.
Question 20
Simplify , leaving your answer in standard form.
Options: A. B.
C.
D.
[2007 Q3]
Step 1: Divide the numbers
and the powers of 10 separately.
Step 2: Combine.
Step 3: Put it in standard
form. , so
Answer: B.
Question 21
Express the square root of
0.000144 in standard form.
Options: A. B.
C.
D.
[2009 Q6]
Step 1: Write the number
as a whole number times a power of 10.
Step 2: Take the square
root of each part.
Step 3: Standard form.
Answer: C.
Question 22
Multiply by
and leave
your answer in standard form.
Options: A. B.
C.
D.
[2013 Q1]
Step 1: Multiply the
numbers, then the powers of 10.
Step 2: Combine.
Step 3: Standard form. The first number must be between 1 and 10, so .
Answer: C.
Question 23
Evaluate
Options: A. 1 B. 2.02 C.
20.02 D. 202 [1988 Q1]
Step 1: Use the difference
of two squares.
Step 2: Work out each
bracket.
Answer: D.
Question 24
Simplify
Options: A. 0 B. C.
D.
[1988 Q3]
Step 1: Work out each
part.
Step 2: Multiply.
Answer: D.
Question 25
Which of the following is
equal to ?
Options: A. B.
C.
D.
[1994 Q2]
Step 1: Break 72 into
prime factors.
Step 2: Break 125 into
prime factors.
Step 3: Combine.
Answer: A.
Question 26
Evaluate
Options: A. 6 B. 5 C. 4 D. 3
[1994 Q4]
Step 1: Top.
Step 2: Bottom. The negative power means flip.
Step 3: Divide. Dividing by is the
same as multiplying by 2.
Answer: A.
Question 27
Simplify
Options: A. 0 B. 2 C. 4 D. 10
[1994 Q5]
Step 1: Work out each
part.
Step 2: Multiply.
Answer: C.
Question 28
Given that , find
.
Options: A. B.
C.
D.
[1999 Q24]
Step 1: Take the square
root of each part of .
Step 2: Multiply.
Answer: C.
Question 29
Solve the equation .
Options: A. B.
C.
D.
[2005 Q12]
Step 1: Change 8 to base
2.
Step 2: Equate the powers
and solve.
Answer: B.
Question 30
Simplify
Options: A. B.
C.
D.
[1996 Q4]
Step 1: Divide the
numbers.
Step 2: Divide the powers
of (subtract
the powers).
Step 3: Combine.
Answer: D.
Question 31
Simplify
Options: A. B. 3 C.
D.
[1995 Q4]
Step 1: Write 0.027 as a
fraction.
Step 2: Flip the fraction to remove the negative sign.
Step 3: Take the cube root
of top and bottom.
Answer: D.
Question 32
Simplify
Options: A. 1 B. C.
D.
[1989 Q32]
Step 1: Top.
Step 2: Bottom. Take the cube root first, then square.
Step 3: Divide.
Answer: D.
Question 33
Simplify
Options: A. 350 B. 35 C. D.
[1990 Q1]
Step 1: Work out each
part.
Step 2: Multiply.
Answer: C.
Question 34
If , what is
?
Options: A. 1 B. 1.5 C. 4.5
D. 18 [1990 Q2]
Step 1: Write 27 as a
power of 3. .
Step 2: Equate the powers.
Answer: B.
Question 35
Simplify
Options: A. 8 B. 4 C. D.
[1998 Q4]
Step 1: Change the mixed
number. .
Step 2: Flip the fraction to remove the negative sign.
Step 3: Square root first,
then cube.
Answer: A.
Question 36
It is observed that ,
,
. If
, find
.
Options: A. 6 B. 7 C. 8 D. 9
[1999 Q3]
Step 1: Spot the pattern. Adding the first 2 odd numbers gives , the first 3 give
, the first 4 give
. So the first
odd
numbers add up to
.
Step 2: Count the numbers in . There are 8 of them.
Step 3: Use the pattern.
Step 4: Find .
, so
.
Answer: C.
Question 37
Simplify
Options: A. B.
C.
D. 4 [1998
Q7]
Step 1: Work out each
part.
Step 2: Put the numbers
in.
Answer: C.
Question 38
Given that , find
.
Options: A. B.
C.
D. 2 [2000
Q29]
Step 1: Change to base 3.
Step 2: Equate the powers
and solve.
Answer: B.
Question 39
Simplify
Options: A. B.
C.
D.
[1991Q10]
Step 1: Write as a
power of 2.
.
Step 2: Multiply it into
each term (add the powers).
Step 3: Put it together.
Answer: A.
Question 40
Simplify
Options: A. B.
C.
D.
[1992 Q7]
Step 1: Write the top and
bottom as fourth powers. and
.
Step 2: Take the fourth
root.
Answer: D.
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How to Prepare for Indices Questions in 2027 Examinations
- Try not to just regurgitate the six laws.
- Practise applying them.
- Begin with some easy multiplication and division problems.
- Then move to:
- Negative indices
- Fractional indices
- Write expressions with multiple variables
- Equations involving indices
- Word problems
- Mixed examination questions
- The more variations of questions you practice, the more you will be able to see which is the proper approach.
Common Mistakes Students Make in Indices
- Incorrectly adding indices to the divisor during division.Error 1: Adding indices to the divisor when dividing.
- One of the common mistakes students make is adding indices when raising a power to another power, as in the following: x^2^2^y^2^ = x^?^y^?^
- Suppose the answer is negative, because of the negative index.
- Not remembering the meaning of fractional exponents as roots.
- Solving an index equation without first having to make the bases equal.

