At a family gathering, Grandma hides five differently shaped presents for her grandchildren - a square, a circle, a triangle, a star, and a heart - in various locations around the house. She tells the children that each present corresponds to a specific grandchild. However, while Grandma is preparing dinner, Grandpa decides to rearrange the presents so that each child finds a different shape than what Grandma intended. He also adds a sixth hexagon-shaped present as a surprise. How do the grandchildren know which present was meant for them when they start searching? Provide a short response.
The grandchildren cannot be certain which present was originally intended for them by Grandma since Grandpa rearranged the presents, and they were not privy to Grandma's original assignments. The introduction of the sixth hexagon-shaped present by Grandpa further complicates the matter, as it does not correspond to Grandma's initial arrangement of five differently shaped presents.

One potential way for the grandchildren to deduce which present is theirs is by considering Grandma's personality, past gift-giving patterns, or any personal connections they might have with specific shapes. However, without a direct clue or confirmation from Grandma or Grandpa, identifying the intended presents with certainty is not possible based on the information given. The children may need to ask Grandma or Grandpa for hints or clarification to know which present was meant for them.