For each problem type, the dividend and the divisor have common denominator, meaning that they are expressed using same size units.
During initial discussions about what fraction division problems are asking, presenting problems with common denominators can easily highlight important mathematical ideas.
For example, see part A of the Hamburger problem: Solving this division situation involves finding how many groups of three 1/10 size units are in nine 1/10 size units.
This problem parallels reasoning that students have used with the whole-number division problem 9 ÷ 3 = 3 when finding how many groups of three are in nine.
Figure 3 highlights models that students developed when solving part A of the Hamburger problem.