A child’s invented solution deserves understanding before an explanation of the usual one.

A child who has worked out their own way of doing something has done real thinking, and the method usually contains a reasonable idea even when the answer comes out wrong. Replacing it immediately with the standard version teaches that inventing was a detour, and next time they will wait to be told. What gets lost is the habit of trying.

Ask them to walk you through their way before offering yours. Name the part that was clever. Then show the usual method as another option rather than as a correction.