WHICH ONE DOESN’T BELONG?
Exploring Math Routines
WHICH ONE DOESN’T BELONG? Routine
This math routine promotes metacognition (thinking about your thinking) and mathematical discourse as students use precise language to compare different ideas.
In this routine, students look at all four pictures in each of the squares and are asked to share their reasoning as to "Which One Doesn't Belong” and “Why?" The catch! There are no wrong answers, as long as students’ reasoning is true and can support their claims. Students need to be able to communicate their reasoning or justification of their choices. Each picture doesn’t belong in some way. Can you figure out the reasoning behind each picture?
Try some examples below with your child:
- Think about which picture doesn’t belong with the other pictures.
- Think about why that picture doesn’t belong with the other pictures.
- What is different about that picture?
Kindergarten & Grade 1 Example
Grade 2 Example
Grade 3 Example
Grade 4 Example
Sample Answers
Kindergarten and Grade 1 Example
The circle is the only one with no points or corners.
The rectangle is the only one with all straight sides.
The blue picture is the only one with a missing piece. The rest of the shapes are closed.
The red shape is the only one with curves and straight sides.
Grade 2 Example
The bundles showing 312 doesn’t belong because it’s not the same value as the others.
21 tens 3 ones doesn’t belong because it only tells how many tens and ones, not hundreds.
3 + 10 + 200 does not belong because it is the only expression. It has numbers and symbols.
Two hundred thirteen doesn’t belong because you can’t tell that there are tens in this number. The other boxes show tens in numbers, words, or pictures.
Grade 3 Example
The eggs don't belong because they are arranged in an array and the others show equal groups.
The dice doesn't below because it represents groups of 5 whereas the others represent groups of 2.
e.g., equal groups, array, or scattered). Responses that reason about the representation of 5 and 2 (i.e., number of groups or number in each group) should also be highlighted.
Grade 4 Example
The equation in picture A doesn’t belong because it’s the only one that uses unit form.
The tape diagram in picture C doesn’t belong because it’s the only one that shows the actual groups. You can see 4 groups of 30 and 4 groups of 1.
The equation in picture D doesn’t belong because it’s the only one that shows 31 as 30+1
The number bond in picture B doesn’t belong because it’s the only one that does not show 31 decomposed into 30 and 1.