上册的

7.6×3.7＋24×0.37
=7.6×10×0.37＋24×0.37
=76×0.37＋24×0.37
=（76+24)×0.37
=100×0.37
=37
2.16＋21.6×9.9
=21.6×0.1+21.6×9.9
=21.6×(0.1+9.9)
=21.6×10
=216
17×（□＋0.8）-17×□＋0.8
=17×□+17×0.8-17×□+0.8
=(17×□-17×□)+(17+1)×0.8
=0+18×0.8
=14.4
所以得数相差14.4