Spatial thinking challenge

The figures below are all cut out of identical cubes.

The diagram below shows the front view of the figures in two dimensions.

Question:  What would the figures look like from the top in two dimensions?  Strangely, four of them look the same from above.  Which one is different?

For the solution, click "Read More" below.

The Funny Calculator

A calculator has these buttons:

Just like a “normal” calculator,  

When you type 1 x 10, it says 10.

When you type 1 + 10, it says 11.

But…

When you type 1 + 1, it says 10.

When you type 10 + 10, it says 100.

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Using this information alone:

How would you count from one to four?  

What would the calculator say if you typed in 100 / 10 ?
    

Extending the pattern:


 Can you extend the pattern to count up to twenty?

What would the calculator say if you typed in 0.1 + 0.1?

What would the calculator say if you typed in 0.1 x 10 ?

What would the calculator say if you typed in 111 + 111 ?

What would the calculator say if you typed in 111 x 10 ?

For the solution, click "Read More" below.

Counting triangles!

How many triangles are there in this picture?

It's not so easy.....

For the solution, click "Read More" below.

Digital Clock Problem

The clock below uses columns of dots to represent the time, in minutes and hours.  What time does the clock read?

Use the clues below to decode the number system and read the time on the clock above.

Clues:

For the solution, click "Read More" below.

The Stacked Block Problem

For the solution, click "Read More" below.

More Guess My Word Puzzles

For the solution, click "Read More" below.

Domino Square Puzzle

There are 28 different dominoes in a set.  In the puzzle below, four dominoes from a set are placed in the shape of a square.  This is a "domino square."

We can make a puzzle out of a domino square by trying to arrange it so that we have the same number of "pips" (or dots) along each edge of the square.  It could be any number, it just has to be the same one each side.

Notice that the domino square below almost works -- it has 10 pips along three of the four edges, but the botton edge has only 7 pips.

Can you fix this square by replacing one of the dominoes so that every side has 10 pips?  Remember that the dominoes must all be different.

How many domino squares can you make with a single set of dominoes?

For the solution, click "Read More" below.