\(a,17.93+116.83+17.23\)
\(=17.\left(93+23\right)+116.83\)
\(=116.\left(17+83\right)\)
\(=116.100\)
\(=11600\)
\(b,19.27+47.81+19.20\)
\(=19.\left(27+20\right)+47.81\)
\(=47.\left(19+81\right)\)
\(=47.100\)
\(=4700\)
\(c,87.23+13.93+70.87\)
\(=87.\left(23+70\right)+13.93\)
\(=93.\left(87+13\right)\)
\(=93.100\)
\(=9300\)
\(d,78.31+78.24+78.17+22.72\)
\(=78.\left(31+24+17\right)+22.72\)
\(=72.\left(78+22\right)\)
\(=78.100\)
\(=7800\)