Students have a hard time subtracting "unfriendly" fractions where the second fraction part is larger than the first (ie. 3 1/3 - 2 2/3). To simplify this and build conceptual understanding I teach students to stack, count and open pizza boxes to solve these problems. Students use manipulatives and I explain it with whole, filled boxes, partial filled boxes and pieces on the table. Then they can "open" a box and place the pieces back on the table (fraction dividing line - denominator is amount in the box, numerator is amount on the table) to make the problem understandable. - Download comes with a colorful visual display of the steps to problem solving, colorful graphic parts to cut out, laminate and magnetize for white board lessons, and a student worksheet to check for understanding.