L4 · Bar graphs with one-to-one correspondence
“I can build and read a bar graph with one-to-one correspondence: the axis counts by 1s, and each bar's height is exactly the count for its group.”
Our class asked: "Which recess activity do students choose most?" The counts are: Tag 7, Swings 5, Soccer 9, Reading 4. Step 1: Draw the AXIS counting by 1s: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Every step on the axis is exactly 1 student - this is one-to-one correspondence on a bar graph. Step 2: Draw one bar per activity, rising to its count: Tag's bar stops at the line labelled 7; Swings at 5; Soccer at 9; Reading at 4. Step 3: Add the TITLE: "Recess Activities Students Choose." A graph without a title does not say what it shows. Step 4: Check. The tallest bar is Soccer (9) - soccer was chosen most. The bar heights added together are the counts: 7 + 5 + 9 + 4 = 25 students. Say it plainly: to read a bar, travel from its top straight across to the axis. The label it touches is the count.
Why does this axis count by 1s instead of by 5s or 10s?
A fifth activity, Drawing, got 6 students. Describe its bar. -> A bar that stops exactly at the line labelled 6 on the axis
"To read a bar: start at the bar's ___, travel straight across to the ___, and read the ___ it touches." -> top; axis; label (number)
10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.