239×101的简便计算=239x（100+1）=239x100+239=23900+239=24139
239x101 = 239x(100+1) = 239x100 + 239x1 = 23900 +239 = 24139
239X101=239X（100+1）=239X100+239=23900+239=24139
=239×（100+1）=239×100+239=23900+239=24139
