78×(301-199)
=78×[(300+1)-(200-1)]
=78×(300-200+2)
=78×(100+2)
=78×100+78×2
=7800+156
=7956
900÷75+900÷25
=300÷25+900÷25
=(300+900)÷25
=1200÷25
=12×100÷25
=12×4
=48