NOTE: The answers below represent just ONE of the many reasons that each item could be eliminated. There are certainly more reasons than the ones given. The primary goals of this Number Sense routine is to generate discussion around topics of mathematics, patterns, and relationships.
SHELLS
- TOP LEFT is the only one that has the bottom showing. The other three have the top of the shell showing (orientation of the shell)
- TOP RIGHT is the only one that not mostly black (color of shells)
- BOTTOM LEFT is the only one that is not a conch-type of shell (classification of shells)
- BOTTOM RIGHT is the only one that does not point to the right (rotational position of the shells)
NUMBER SET
- TOP LEFT is the only one that is not a double digit number; it's a single digit number
- TOP RIGHT is the only one that when rounded would not round UP to the next tens place; it would round DOWN to the next tens place value
- BOTTOM LEFT is the only one that is not a multiple of 7 (7x1, 7x3, 7x8)
- BOTTOM RIGHT is the only one that is not an odd number; it's an even number
- TOP LEFT is the only one that has the coins facing tails up
- TOP RIGHT is the only one that does not use silver coins
- BOTTOM LEFT is the only one that is not equal to 25 cents
- BOTTOM RIGHT is the only one that does not use multiple coins
