Addition game: animal bridges

GAME INFO
Sum Bridges for the Animals. Online game to add up lengths, add blocks to the cliff for the animals to cross safely. Add blocks of different lengths, add them together until you build a bridge for the animals, in the style of the cuisenaire blocks. When you have a block that is longer than the length you need, trade this block, moving and pointing to adjacent blocks that add up to the same amount, until you reach a block that allows you to complete the three bridges for the three animals. Click on swap to trade blocks, exchanging for example a block of length 9, having marked adjacent blocks of 5 + 3 + 1.