用简便方法计算下面各题，不用简便计算的不给分．4.6+325+635+5.40.25×32×12.5999×778+333×66656×113+59×213+518×613．

Question

用简便方法计算下面各题，不用简便计算的不给分．
4.6+3(2)/(5)+6(3)/(5)+5.4                 
0.25×32×12.5
999×778+333×666                   
(5)/(6)×(1)/(13)+(5)/(9)×(2)/(13)+(5)/(18)×(6)/(13)．

Answer 1

（1）4.6+3(2)/(5)+6(3)/(5)+5.4   
=（4.6+5.4）+（3(2)/(5)+6(3)/(5)）         
=10+10
=20；
    
（2）0.25×32×12.5
=0.25×4×8×12.5
=（0.25×4）×（8×12.5）
=1×100
=100；

（3）999×778+333×666 
=999×778+333×3×222
=999×778+999×222
=999×（778+222）
=999×1000
=999000；
             
（4）(5)/(6)×(1)/(13)+(5)/(9)×(2)/(13)+(5)/(18)×(6)/(13)
=(1)/(6)×(5)/(13)+(2)/(9)×(5)/(13)+(6)/(18)×(5)/(13)
=（(1)/(6)+(2)/(9)+(6)/(18)）×(5)/(13)
=(13)/(18)×(5)/(13)
=(5)/(18)．