5.32+2.06+19.4+1.84+7.68=(5.32+7.68)+(2.06+1.84)+19.4=13+3.9+19.4=36.3
5.32+2.06+19.4+1.84+7.68＝（5.32+7.68）+（2.06+1.84）+19.4＝13+3.9+19.4＝36.3
