Equal-Side Triangle: Balance All Three Sides to One Target Sum
Generate six fresh numbers and a common side total with a guaranteed triangle solution.
Guessing Corners Stalls Out: Their Total Must Be a Multiple of Three
Generate six fresh numbers and a common side total with a guaranteed triangle solution. Retry keeps the current level; New set changes the number pool and target, accepting different valid arrangements.
Spotting a Multiple of Three Grows Number Sense in Grades 3-5
The puzzle picks up right after students learn to add three single-digit numbers fluently (1.OA.A.2) and pushes that skill into a reason-first habit: before moving pieces, decide whether a corner trio can work by testing it against the multiple-of-three rule. That is early divisibility and structure thinking—the same judgment behind checking whether an answer is reasonable in two-step problems (3.OA.D.8) and the multi-step word problems of fourth grade (4.OA.A.3). Re-adding each side after a swap keeps addition within 20 sharp.
Three Skills Practiced in Equal-Side Triangle
- adding three values to a target sum
- recognizing that one node can belong to two constraints
- using elimination and organized trials
Teacher and Parent Note
Ask the student to mark why corner values have more influence than middle positions. Record all three side sums after each swap and use the table to decide whether the move reduced the imbalance.