a) 25.5.4.31.2
=(25.4).(5.2).31
=100.10.31
=1000.31
=31000
a: \(25\cdot5\cdot4\cdot31\cdot2=31000\)
b: \(62+98\cdot31=3100\)
a) 25.5.4.31.2
= 25.4.5.2.31
= 100.10.31
= 1000.31
= 31000
b) 62.98.31
= 31.2.31.1.98
= 31.(2+1).98
= 31.3.98
= 93.98
= 93.(100-2)
= 93.100-93.2
= 9300-186
= 9114
Chúc bạn học tốt !