Grade
K

How Many Are Hidden? Shifting Shapes

What do you notice? How many shapes do you see?

A large triangle made with smaller shapes. The top row is 1 small triangle. The middle row is 1 trapezoid. The bottom row has 2 small triangles, a rhombus, and then 1 more small triangle.

Now some shapes are hiding behind the big square.
How many are hidden? Use math words, numbers, or pictures to explain how you know.

The top parts of the big triangle are hidden. The bottom row is still 2 small triangles, a rhombus, and 1 more small triangle.

Challenge

Now we can see which shapes were hiding! What equations match the picture? How do you know?

The bottom of the large triangle has four shapes. The top part of the triangle has 2 shapes.

6 − 2 = 4

6 = 3 + 3

4 + 2 = 6

5 + 1 = 6

Follow-up

How could you remove different shapes from the large triangle to make a smaller triangle?

A large triangle made with smaller shapes. The top row is 1 small triangle. The middle row is 1 trapezoid. The bottom row has 2 small triangles, a rhombus, and then 1 more small triangle.
Printable Version

Google doc for printing and copying

Seesaw Version

Activity for the Seesaw platform

Reference for Educators

Sample problems and solutions