7th Grade > Mathematics
FRACTIONS AND DECIMALS MCQs
Fractions, Decimals
:
B
In order to reduce a fraction to its lowest terms, divide both numerator and denominator by their common factor.
13860101848010=13861848
1386318483=462616
4621161611=4256
427567=68=34
:
D
In order to convert the fractions into like fractions, find the L.C.M of denominators of given fractions.
Then convert each fraction into an equivalent fraction having denominator as the L.C.M of the denominators of the given fractions.
L.C.M of [12, 4, 3] = 12
612=6×112×1=612
14=1×34×3=312
63=6×43×4=2412
:
A
3a4 is a mixed fraction.
3a4= (3×4) +a4= 12 +a4
Given, (12+a)4 = 154
Comparing the numerator gives, (12 + a) =15
Therefore, a = (15 - 12) = 3
:
B
To compare the fractions, make the denominators equal.
For that, we have to find LCM of denominators 16,9,10
16=2×2×2×2
9=3×3
10=2×5
LCM of [16, 9, 10] = 2×2×2×2×3×3×5=720
1216=12×4516×45=540720
49=4×809×80=320720
610=6×7210×72=432720
Comparing numerators, 320720<432720<540720
∴49<610<1216
:
C
One fraction exisiting between ab and cd is a +cb +d.
Here, we have to insert a fraction between 29 and 619.
a = 2, b = 9, c = 6 and d = 19
One fraction exisiting between them is: 2 +69 +19 = 828
:
D
Decimal numbers having the same number of decimal places, i.e. decimals having the same number of digits on the right of the decimal point, are known as like decimals.
In the option with the numbers 9865.4946 and 28.4900, both decimal numbers have 4 digits in the decimal place.
Therefore, they are like decimals.
The rest of the options do not have same number of decimal places.
:
A and C
A very important property of decimals is that adding zeros after the last digit of the decimal part of any decimal number does not change the value of the decimal.
Hence,
10.0101, 10.01010 and
0.1010, 0.1010000 are the right options
:
Answer: 1 Mark
Let the number be x
Given x×165 = 1
Hence, x = 30
The least value of the number is 30
:
Steps: 1 Mark
Answer: 1 Mark
3.2 km = 3200 metres
Given that
Distance covered in 16 seconds = 3200 metres
Distance covered in 1 second = (3200÷16)
= 200 metres.
1 minute = 60 seconds
Distance covered in 1 minute =60×200
=12000m
The distance covered in 1 minute is 12000 metres.
:
Each option: 1 Mark
Now, 79,23,421
The LCM of the denominators of the above fractions = 63
⇒7×79×7, 2×213×21, 4×321×3
⇒4963, 4263, 1263
Hence, arranging in descending order we have
4963>4263>1263
i.e., 79>23>421
(ii) The LCM of the denominators of the given fractions = 105
Making them like fractions. We have,
1×353×35, 4×215×21, 6×157×15
35105, 84105, 90105
⇒67>45>13