Or search by topic
Can You Make 100? printable sheet
How many ways can you find to put operation signs ($+$, $-$, $\times$, $\div$) between the digits make $100$?
Click here for a poster of this problem.
Bluey-green, white and transparent squares with a few odd bits of shapes around the perimeter. But, how many squares are there of each type in the complete circle? Study the picture and make an estimate.