简便 49.5/9+35.1/7.8 {2.5-8分之31/（6分之11+0.75）}*17分之30 19.63*99+

49.5/9+35.1/7.8
=5.5+4.5
=10
{2.5-8分之31/（6分之11+0.75）}*17分之30
={2.5-31/8÷31/12}×30/17
={2.5-1.5}×30/17
=30/17
19.63*99+19.63
=19.63×（99+1）
=19.63×100
=1963
（76-105*0.6）*13分10
=（76-63）×10/13
=13×10/10
=10