Free Rational Numbers 03 Practice Test - 7th grade
Question 1
The sum of three rational numbers is −15.If two numbers are −25 and 310, then find the third number.
810
110
−110
−210
SOLUTION
Solution : C
Let the unknown number be x.
−15=310+−25+xx=−15−310+25
Taking LCM, we get,x=−210−310+410x=−110
Question 2
What is the quotient, when a non-zero rational number is divided by its additive inverse?
0
-1
1
2
SOLUTION
Solution : B
Let pq be a non-zero rational number. Then p, q≠0.
Its additive inverse is −pq.
That is, pq+−pq=−pq+pq=0
On dividing pq by −pq, we get -1.
Question 3
Which of the following is obtained by the subtraction of 1/2 from its reciprocal
SOLUTION
Solution : B
Question 4
From a rope of length 40.50 m, some
pieces are cut each measuring 94 m.
Find the number of pieces cut.
15
18
22
9
SOLUTION
Solution : B
Converting all the lengths into centimetre.
Total length of the rope = 4050 cm,
Length of each piece
=94×100=9004
Number of Pieces
=Total lengthLength of each pieceNumber Of Pieces Cut
=4050(9×100)4=18
=4050×4(9×100)=18Number of pieces cut = 18.
Question 5
What number must be subtracted from
14 to get 12?
12
−14
1
-1
SOLUTION
Solution : B
Let the number be x.
14−x=12
x=14−12=−14
Question 6
Find the value of x such that −11x is not a rational number.
1
2
-1
0
SOLUTION
Solution : D
A number which can be written in the form pq , where p and q are integers and q ≠ 0 is called a rational number.
By the above definition, pq can be a rational number only when q ≠ 0.
So, for the given fraction to be not a rational number, x should be zero.
For all the other given values of x, we will obtain a rational number.
For example, when x = 1,
−11x=−111=−11
when x = 2,
−11x=−112=−5.5
when x = -1,
−11x=−11−1=11
Question 7
What should be added to −34 to get 516?
1216
1316
1116
1716
SOLUTION
Solution : D
Let the number to be added be x.
−34+x=516
x=516+34=516+1216=1716.
Question 8
Write a rational number equivalent to 23 whose numerator is 8.
821
812
815
820
SOLUTION
Solution : B
Consider 23.
To make the numerator 8, we have to multiply the numerator by 4.Therefore, multiplying both numerator and denominator by 4 gives the required number.
2×43×4=812Therefore, required rational number is 812.
Question 9
4422 in simplified form is
SOLUTION
Solution :4422=21 [Dividing both numerator and denominator by 22]
21=2
Question 10
State whether the following is true or false.
-1413<16
True
False
SOLUTION
Solution : A
By using the number line, we know that the statement is true.
