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Let's Investigate Triangles

Vincent and Tara are making triangles with the class construction set. They have a pile of strips of different lengths. How many different triangles can they make?


Noah saw 12 legs walk by into the Ark. How many creatures did he see?

More Numbers in the Ring

Age 5 to 7
Challenge Level

Vidhya from Kensri School in India sent in a very well reasoned solution:

When we subtract an even number from an odd number, or vice versa, the difference is always odd. So if we fill up odd numbers and even numbers alternately, if there are an even number of squares, the differences will all be odd. But there is no solution (in other words the differences cannot all be odd) if there is an odd number of squares.