Problem
Line up each item's orange and yellow-green bars — the gap between their tops is the difference between the two color counts.
The height gap between the paired bars is exactly how many more of one color there are.
3.MD.B.3Identify SubproblemsFor each item, the height gap between the tops of its two bars equals the difference between its orange count and its yellow-green count.
Both bars in a pair are measured on the same height scale, so each bar's height stands for its count and the taller bar really does show the larger number.
Every equal step of bar height is matched with one counted object, so bars of equal height mean equal counts and a taller bar means more objects.
The taller bar is a part that matches the shorter bar exactly plus an extra piece with nothing to match, and that extra piece is the height gap.
Each unit in the shorter bar pairs with one unit at the bottom of the taller bar, so those matched parts are the same size.
The taller bar splits with no overlap into the matched part and the leftover part, so those two parts add back to the whole taller bar.
Taking the shorter count away from the taller count undoes adding it on, so what is left is exactly that extra piece — the difference.
Set the two gaps side by side: the crayon pair shows a clearly wider gap than the colored-pencil pair.
The bigger the visible gap between a paired item's bars, the bigger the difference between its two colors.
3.MD.B.3Draw A DiagramThis only needs Grade 3 graph reading: the widest gap between a pair of bars wins!