Reading a dot plot

What it looks like when your child can do it

• — Shown a dot plot of pages read each night, your child counts the dots and says how many nights there were.
• — Your child points to the tallest stack, names the value under it, and says it is the most common answer.
• — Your child reads the leftmost and rightmost dots and says how far apart they are.

How to teach it at the kitchen table

1. 01

   Draw the number line first

   Draw a line across the page and mark whole numbers evenly, such as 4 to 12 for pages read in a night. Graph paper keeps the spacing even. Every dot will sit above one of those numbers.

2. 02

   One dot for each answer

   Take a list, like pages read on 12 nights: 5, 6, 6, 7, 7, 7, 7, 8, 8, 9, 10, 12. For each answer, put one dot above its number. When a number repeats, stack the new dot on top of the one already there.

3. 03

   Count the dots

   The number of dots is the number of answers, not any number on the line. Twelve nights means twelve dots. Have your child check the count against the list.

4. 04

   Find the pile and the two ends

   The tallest stack is the most common answer, here 7 pages with 4 dots. The leftmost dot is the smallest answer, 5, and the rightmost is the largest, 12. The distance between them, 12 - 5 = 7 pages, is how far the answers spread.

5. 05

   Turn the plot back into a list

   Have your child read the plot from left to right and write one value for every dot. If the list matches the one you started with, the plot is being read correctly.

You will need: Graph paper and a pencil · A handful of coins or buttons for stacking

Try it together

1. Try 1

   Draw a number line from 6 to 12. Your child's hours of sleep for 10 nights were 7, 8, 8, 9, 9, 9, 9, 10, 10 and 11. Make the dot plot together, then ask how many dots there are.

   Listen for  10 dots, one for each night. Watch that the four 9s stack into one tower instead of spreading out sideways.

2. Try 2

   Using the same plot, ask which value has the tallest stack.

   Listen for  9 hours, with 4 dots. That is the most common answer. A child who says 4 gave the height of the stack, not the value under it.

3. Try 3

   Ask for the shortest night, the longest night, and how far apart they are.

   Listen for  The shortest is 7 hours and the longest is 11 hours, so they are 11 - 7 = 4 hours apart. That spread is a distance in hours, not a count of dots.

4. Try 4

   Ask on how many nights your child slept 10 hours or more.

   Listen for  3 nights: two at 10 and one at 11. This takes adding two stacks together, so it is the stretch question.

5. Try 5

   Draw a new plot: one dot at 3, two at 4, three at 5, one at 6 and one at 12. Ask which dot looks different from the rest.

   Listen for  The dot at 12. The other 7 dots sit together from 3 to 6, and this one sits far off by itself. Noticing a far-off dot is where describing a plot's shape begins.

Watch for

• — Mixing up the value and the count. The tallest stack sits over 9 and has 4 dots, so the answer to which value is 9 and the answer to how many is 4.
• — Uneven spacing on a hand-drawn line, which makes some stacks look farther apart than they are. Graph paper fixes it.

If it is not there yet

• — Go back to a short list of 5 answers on a line from 0 to 5, and stack real coins or buttons above each number before switching to pencil dots.
• — Practice reading a number line on its own until your child can find any whole number on it quickly.

A few days of this is normal, and it is time well spent. The lesson will still be there, and it will go faster.

Where this skill comes up

• Grade 6 Math Practice Workbook · Lesson 30

  Center, Spread, and Shape

  Needs it because the description is read off the plot.