Simply show these images and ask your students "How many do you see?"
The students could:
- Count the total dots
- Number of dice
- Number of colors
- Number of dots on a certain dice
- Number of dots on a certain part of the pattern
I would provide students white boards (or have them at non permanent table tops) and have them write down how they know.
After 2 or 3 minutes, simply start the conversations and reply to every answer "How do you know?".
Remember, during this time try to ask more questions than give answers.
Here is a slideshow showing different possible pictures.