(10十1)X52=10X52十1X52=520十52=572 (10十1)X52=11X52=11X(50十2)=11X50十11Ⅹ2=550十22=572
方法1:(10+1)×52=10×52+1×52=520+52=572,方法2:(10+1)×52=11×52=11×50+11×2=550+22=572