Problem
Class 3 (4 circles) has 4 more students than Class 2 (3 circles), so one circle equals 4 students.
Class 3's students split into 'as many as Class 2' plus the students shown by the one extra circle, so that extra circle carries the whole 4-student gap between them. Every circle stands for the same number of students, so if one circle is worth 4, each circle is worth 4.
Analyze The Units3.MD.B.3Tables And GraphsOn this graph, one circle stands for 4 students.
Class 3 is drawn with one more circle than Class 2, yet in real students Class 3 has just 4 more than Class 2, so that single extra circle is worth exactly those 4 students.
Class 3's students split into 'as many as Class 2' plus the students shown by the one extra circle, so that extra circle carries the whole 4-student gap between them.
Every circle in a column stands for the same number of students, so if one circle is worth 4 then each circle is worth 4.
With 4 students per circle, Class 2 is 3×4=12 and Class 3 is 4×4=16 students.
Once one circle is known to be a group of 4 students, Class 2's 3 circles and Class 3's 4 circles are just that many equal groups of 4. Counting equal groups with multiplication, circles × 4, gives the real student counts.
Analyze The Units3.MD.B.3Subtracting 16+12+16 from the total of 56 leaves 12 students in Class 4.
The total of 56 is Class 1 plus Class 2 plus Class 3 plus Class 4 added together, so subtracting the three already-known classes (16, 12, 16) from 56 leaves exactly Class 4's student count.
Identify Subproblems3.OA.A.3Dividing each class by 4 gives 4, 3, 4, and 3 circles — draw that many in each column to finish.
Since one circle stands for 4 students, dividing each class's student count by 4 gives the number of circles to draw for that class. Filling that many circles from the bottom up completes the graph.
Identify Subproblems3.MD.B.3Tables And GraphsMatch a drawn circle-count difference to a known student-count difference to find one circle's value first.