Вычисли удобным способом: 420:(10 * 7)=7 5400:( 100*3)=? 7200:(9*4)=?

Вычислим удобным способом:

1) 420 : (10 * 7) = (42 * 10)/(10 * 7) = (42 * 1)/(1 * 7) = 42/7 = (6 * 7)/7 = 6 * 1/1 = 6/1 = 6; 

2) 5400 : (100 * 3) = (54 * 100)/(100 * 3) = (54 * 1)/(1 * 3) = 54/3 = 18 * 3/3 = 18 * 1/1 = 18/1 = 18; 

3) 7200 : (9 * 4) =  (9 * 800)/(9 * 4) = (1 * 800)/(1 * 4) = 800/4 = 200 * 4/4 = 200 * 1/1 = 200/1 = 200.