{20分之1减4分之3}乘
=(1/20-15/20)×(10/14-5/14)
=-7/10×5/14
=-1/4
负10加8除以负2的平方减负4乘负3
=-10+8÷4-4×3
=-10+2-12
=-8-12
=-20
负5分之9乘负3分之5的平方加负8分之3除以
=9/5×25/3-3/8÷(-1/8-1/4)
=15+3/8÷3/8
=15+1
=16