Every side of the triangle must add up to the same sum.
Write the missing numbers into the circles so
that every side makes the target sum.
Every side of the triangle must add up to the same sum.
Example
What does this exercise practice?
This exercise builds combinatorial thinking: children understand that one number can play several roles at once, because corner points belong to two sides.
Common pitfalls
Children forget that each corner number contributes to two sides. Let them mark the corner points first and add up both sides separately, before they fill in a number.
How to practice at home
Draw a triangle on paper with six circles and lay out six coins. Can you place the coins so that all three sides make the same sum? Trying is allowed!
Related: Magic square, Number cross