A rectangular chocolate bar is made of equal squares. Irena breaks off two complete strips of squares and eats the 12 squares sh
e obtains. Later, Jack breaks off one complete strip of squares from the same bar and eats the 9 squares he obtains. How many squares of chocolate are left in the bar?
We know that Irena breaks off 2 complete strips and eats 12 meaning each strip had 6 squares. Jack breaks off 9. So if we add all the squares into rows of 6, we get four strips of chocolate from the beginning. Since Jack and Irena obtained 21 chocolate squares altogether, we have 3 chocolate squares that are remaining. I hope this helps ;)
