a)45x32+45x66+45+45
=45x(32+66+1+1)
=45x100
=4500
a.45.32+45.66+45.2
= 45.(32+66+2)
=45.100=4500
b.(2013+2014+2015).(20+10).12-18.20
=(2013+2014+2015).(30.12-(12+6).20)
=(2013+2014+2015).(30*12-12.20-6.20)
=(2013+2014+2015).(12.(30-20)-6.20)
=(2013+2014+2015).(12.10-6.20)
=(2013+2014+2015).(120-120)
=(2013+2014+2015).0
=0
c.(12+12+12.88).45+12.12
=(12.(1+1+88)).45+12.10
=12.90.45+120
=12.9.10.5.9+120
=1080.5.9+120
=5400.9+120
=48600+120
=48720
nho k cho to nhe