1st. Move the decimal number 2 spaces to the right. 2.16=216 You need 21 ten rods and 6 cubes. Why: I wouldn't do 2 hundred flats because 2 isn't divisible by 3. Put the ten rods into 3 equal group, then do the same with the cubes. 21/3=7, end up with 7. You should also end up with 2 cubes in each group. 1 group=72. Move decimal back to spaces 2 the left(before we did right, now do opposite) Answer is 0.72