The number of coloured squares = 15
Fraction = \(\cfrac { 15 }{ 30 } \) 

\(\frac{0.399}{2.1} =\frac{\frac{399}{1000}}{21}=\frac{399}{1000} \times \frac{10}{21} \)
\(=\frac{1}{100} \times \frac{399}{21}=\frac{19}{100}=0.19 \)
 

\(0.9 \div 10=\frac{0.9}{10}=\frac{9}{10} \times \frac{1}{10}=\frac{9}{100}=0.09\)

\(453.03 \times 7=\frac{45303}{100} \times \frac{7}{1}=\frac{317121}{100}\)
= 3171.21

Underline the digit to be rounded 1.23
The digit next to the underlined digit is 2 which is less than 5, the underlined digit remains the same.
Hence the rounded value of 1.23 to the nearest whole number is 1

\(\text { Mean }=\frac{\text { Sum of observations }}{\text { Number of observations }}\)
Sum of observations = Mean x Number of observations
= 85 x 15
Sum of observations = 1275
Sum of new observations = 1275 + (Correct observations) - (Wrong observations)
= 1275 + 28 - 73
Correct total =.1230
Correct Mean \(=\frac{\text { Correct total }}{\text { Number of observations }} \)
\(=\frac{1230}{15}=82 \)
Correct Mean = 82

Let the Principal be Rs.100
Time n = 4 years
Rate of the interest r%
Amount = Rs.2 x 100 = Rs.200
Simple interest I = Rs.200 - Rs.100 = Rs.100
\(\cfrac { Pnr }{ 100 } =Rs.100\)

Rate of interest r = 25%

Amount A = Rs.53466
Principal P = Rs.46900
Simple interest I = A - P
= 53466 - 46900 = Rs.6566
Time n = 2 years
Let rate of interest be r%
Simple interest i = \(\cfrac { Pnr }{ 100 } \) = Rs.6566

Rate of the interest r = 7%

Correct answer = 35
Incorrect answer = 10
Total questions = 45

Principal = Rs.48,000
Time n = 3 years and 2 month = 2 1/4 = 9/4 years
Rate of interest = r%
Amount = Rs.55,560
Principal = 48,000
Simple interest I = Rs.7,560
Simple interest I = \(\cfrac { Pnr }{ 100 }\) 

Rate of interest r = 7%

Perennial flowers = \(\cfrac { 30 }{ 40 }\)

Let the marked price = Rs. 100
Discount = 25%
The marked price = \(\cfrac { 100 }{ 75 } \times 1000 =\cfrac { 4000 }{ 3 } \) = Rs.1333.3 = Rs.1334
The marked price = Rs.1334

The percentage of comedy magazines = 20%

Number of pages printed by a printer per minute = 15 pages
Number of pages printed by a printer in 4.6 minutes = 15 x 4.6
\(=\frac{46}{10} \times 15=\frac{690}{10}\)
= 69 pages

Distance walked by a man around a circular park = 23.761m
Distance covered in 100 rounds = 100 x 23.761
= 2376.1 m

\(18.9 \div 1000 =\frac{18.9}{1000}=\frac{189}{10} \times \frac{1}{1000} \)
\(=\frac{189}{10000}=0.0189 \)

\(0.5 \times 3=\frac{5}{10} \times \frac{3}{1}=\frac{15}{10}=1.5\)

Cost of a geometry box purchased by Akilan = Rs. 25.75
Cost of a pencil purchased by Akilan = Rs. 03.75
Cost of a pen purchased by Akilan = Rs. 50.00
Total = Rs. 79.50
Amount remitted to shopkeeper = Rs. 50.00
Balance Amount = Rs. 29.50
Therefore, Amount get back by Alilan from shopkeeper = Rs. 29.50

Let the decimal number be 'x'
Now, 7.1 - x = 0.713
7.1 - x + x = 0.713 + x
(Add 'x' on both sides)
0.713 + x = 7.1
x = 7.1 - 0.713
x = 6.387
Therefore 6.387 to be subracted

First add 23.5 + 35,4

Secondly add negative numbers

Thirdly,

underline the digit to be rounded 5.992
Since the digit next to the underlined digit is 9, which is more than 5. Therefore we should add 1 to the underlined digit
Hence we get 5.9 + 0.1 = 6.