Question 13: Calculate: \(A = – 5.13:\left( {5{5 \over {28}} – 1{8 \over 9}.1.25 + 1{{16} \over {63} }} \right) \)

\(\eqalign{
& A = – 5.13:\left( {5{5 \over {28}} – 1{8 \over 9}.1.25 + 1{{16} \over {63}}} \right) \ cr
& = – 5.13:\left( {5{5 \over {28}} – {17 \over 9}. {5 \over 4} +1{{16} \over {63}}} \right) \cr
& = – 5.13:\left( {5{5 \over {28}} – 2{13 \over 36} +1{{16} \over {63}}} \right) \cr
& = – 5.13:\left( {{{145} \over {28}} – {{85} \over {36}} + {{79} \over {63}}} \right)\cr& = – 5.13:\left( {{{1305} \over {252}} – {{595} \over {252}} + {{316} \over {252}}} \right) \cr
& = – 5.13:{{1026} \over {252}} = {{ – 513} \over {100}}. {{14} \over {57}} = {{ – 63} \over {50}} \cr} \)

So \(A = \dfrac{{ – 63}}{{50}}\)