Problem
Subtract each group's smaller count from its larger: G1 4-3=1, G2 3-3=0, G3 3-1=2, G4 5-2=3.
Reading two stacked columns per group from the graph lets you compare girls and boys directly by subtracting.
2.MD.D.10Make A Systematic ListFor each group, subtracting the smaller count from the larger count gives the difference between the number of girls and boys.
The larger count is really the part that matches the smaller count one for one, plus the extra that has no match, and that extra is the difference.
You can pair each student in the smaller count with one student in the larger count, so the matched parts are the same size.
The larger count splits with no overlap into the matched part and the leftover part, so those two parts add back to the whole larger count.
Taking the smaller count away from the larger count undoes adding it on, so what is left is exactly that extra.
Among the four gaps 1, 0, 2, 3 the largest is 3, which belongs to Group 4.
Interpreting the graph means comparing the bars; the tallest gap wins.
3.MD.B.3Identify SubproblemsGroup 4 has 2 girls and 5 boys, so its total is 2+5=7 students.
The total of a group is just the two columns added together.
2.MD.D.10Identify SubproblemsJust read each pair off the graph, subtract to find the biggest gap, then add that pair up!