There is 20 students in her class.
Ex.
3/10= size of slice; you can get 3 slices from one pizza.
There are 6 pizzas..... 3x6=18; there will be a remained of 1/10 from each pizza because 3/10 is not an even number. Now u would have (6) 1/10's.... So 1/10+1/10+1/10= 3/10 and 1/10+1/10+1/10=3/10..... That makes two more slices for two more students...... 18+2=20 slices for 20 kids in the class! :-)
