A stem-and-leaf plot keeps every value in order. The stem on the left is the tens digit and each leaf on the right is a ones digit, so 3 | 4 8 shows 34 and 38. Use the key to check. Each leaf is one value, even when a leaf repeats. The lowest value is the first leaf in the top row and the highest is the last leaf in the bottom row. For the median, count leaves from the start to the middle value.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- stem
- the tens digit, written once for each row
- leaf
- the ones digit; each leaf is one value
- range
- highest value take away lowest value
Worked examples
1 | 2 5; 2 | 0 3 3; 3 | 4. What is the highest value?
- 1.The highest is the last leaf in the bottom row.
- 2.Stem 3 and leaf 4 make 34.
= 34
Same plot: what is the range?
- 1.Highest 34, lowest 12.
- 2.34 − 12 = 22.
= 22
1 | 2 5; 2 | 0 3 3; 3 | 4 7. What is the median?
- 1.There are 7 values, so the median is the 4th.
- 2.12, 15, 20, 23: the 4th value is 23.
= 23
For parents
Method: Stem is tens, leaf is ones
What to say: Read it with the stem: what whole number does this leaf make?
Common mistakes:
- Reads only the leaf digit and forgets the stem.
- Uses only the stem (as tens) and ignores the leaf.
- Swaps the stem and leaf digits.
- Counts the rows (stems) instead of the leaves.
- Counts a repeated leaf only once.
- Counts the stems as well as the leaves.
- Subtracts the leaves only, ignoring the stems.
- Subtracts the stems only (as tens), ignoring the leaves.
- Gives the highest value as the range.
- Takes the middle leaf of the middle row as the median.
- Gives the position of the median instead of its value.