\(\\ \\ \\ \frac { 1 }{ 1.2 } +\frac { 1 }{ 2.3 } +\frac { 1 }{ 3.4 } +\frac { 1 }{ 4.5 } +\frac { 1 }{ 5.6 } +\frac { 1 }{ 6.7 } +\frac { 1 }{ 7.8 } =\frac { 7 }{ 8 } \)

\(LHS=\frac { 3 }{ 5 } \div \frac { 7 }{ 8 } =\frac { (3\times 8)-(7\times 5) }{ 40 } =\frac { 24-35 }{ 40 } =\frac { -11 }{ 40 } \)
\(RHS=\frac { 7 }{ 8 } -\frac { 3 }{ 5 } =\frac { (7\times 5)-(3\times 8) }{ 40 } =\frac { 35-24 }{ 40 } =\frac { 11 }{ 40 } \)
LHS ≠ RHS
\(\therefore \frac { 3 }{ 5 } \div \frac { 7 }{ 8 } \neq \frac { 7 }{ 8 } -\frac { 3 }{ 5 } \)
∴ Subtraction of rational numbers is not commutative.

\(\frac { -7 }{ 11 } =\frac { -70 }{ 110 } ;\frac { 6 }{ -11 } =\frac { -60 }{ 110 } \)
We have \(\frac { -61 }{ 110 } ,\frac { -62 }{ 110 } ....,\frac { -69 }{ 110 } \) between \(\frac{-7}{11}\) and \(\frac{6}{-11}\)

\(\frac { -6 }{ 4 } =\frac { -6\div 2 }{ 4\div 2 } =\frac { -3\times 11 }{ 2\times 11 } =\frac { -33 }{ 22 } =\frac { 33 }{ -22 } \)
\(\therefore \frac { -6 }{ 4 } \) equivalent to \(\frac { 33 }{ -22 } \)

\(\\ 1.4=\frac { 14 }{ 10 } =\frac { 28 }{ 20 } \)
\(\frac { 1 }{ 4 } =\frac { 1\times 5 }{ 4\times 5 } =\frac { 5 }{ 20 } \)
\(\frac { 28 }{ 20 } >\frac { 5 }{ 20 } \)
\(1.4>\frac { 1 }{ 4 } \)

\(\frac { 7 }{ 36 } \div \frac { 35 }{ 81 } =\frac { 7 }{ 36 } \times \frac { 81 }{ 35 } \)
\(=\frac { 9 }{ 20 } \)

Let the weight of 1 ragi adai = x grams
given \(\frac{1}{4}\) of x = 120 gm
\(\frac{1}{4}\) x x = 120
x = 120 x 4
x = 480gm
∴ \(\frac{2}{3}\) of the adai = \(\frac{2}{3}\) x 480 gm = 2 x 160 gm = 320 gm
\(\frac{2}{3}\) of the weight of adai = 320 gm

1 inch = 120 km
Distance between A and B = 4\(\frac{1}{6}\) inches
Distance between A and C = 3\(\frac{1}{2}\) inches
∴ Distance between Band C = 4\(\frac{1}{6}+3\frac{1}{3}\)inches
\(=\frac { 25 }{ 6 } +\frac { 10 }{ 3 } =\frac { 25 }{ 6 } +\frac { 20 }{ 6 } =\frac { 25+20 }{ 6 } =\frac { 45 }{ 6 } \)inches
1 inch = 120km
∴ \(\frac{45}{6}\) inches =\(\frac{45}{6}\times 120km\) = 900km
Distance between Band C = 900 km

Let the total weight of a box of apple = x kg.
Weight of \(\frac{3}{4}\) of a box apples = 3 kg 225 gm.
= 3.225 kg
\(\frac{3}{4}\times\)x = 3225
x = \(\frac{3.225\times 4}{3}kg\)
= 1..075 x 4 kg
= 4.3 kg
= 4 kg 300 gm
Weight of the box of apples = 4 kg 300 gm

The rational number for the point marked on the number line is 1\(\frac{3}{4}=\frac{7}{4}\)