so cay moi to la
220:5=44
=>neu moi ban dc 5 hoac4 thi so hoc sinh suy ra moi to so chan
so cay de dc 44:
5x4+4x6=44
(5x4 la 4ban trong 5 cay)
(4x6 la 6 bn trong duoc 4cay)
moi to co 6bn trong dc 4cay
=>5to moi to 6bn trong dc 4 cay nen ca lop so bn trong dc 4cay la:
5x6=30bn
ds 30 thang