lam nhu vay ne
2.125.2002.8.5
=(2.5).(125.8).2002
=10.1000.2002
=20020000
c, 28.47+28.43+72.29+72.61
=28.(47+43) +72.(61+29)
=28.90+72.90
=(28+72).90
=100.90=9000
d,26.54+52.73
=(26.2).(54/2)+52.73
=52.27+52.73
=52.(27+73)
=52.100
=5200
b,36.42+2.17.18+9.41.6
=4338
cau nay minh ko tinh nhanh dc
=