50-51+52-53+54-55+56-57+58-59+60
=(-1)+(-1)+(-1)+(-1)+(-1)+60
=(-5)+60
=55
\(A=50-51+52-53+54-55+56-57+58-59+60\)\
\(A=\left(50-51\right)+\left(52-53\right)+\left(54-55\right)+\left(56-57\right)+\left(58-59\right)+60\)
\(A=\left(-1\right)+\left(-1\right)+\left(-1\right)+\left(-1\right)+\left(-1\right)+60\)
\(A=\left(-1\right).5+60\)
\(A=\left(-5\right)+60\)
\(A=55\)
50-51+52-53+54-55+56-57+58-59+60 = 50+(52-51)+(54-53)+(56-55)+(58-57)+(60-59) = 50+ 1 + 1 + 1 + 1 + 1 = 50+ 5 = 55
