Number Patterns

Supriya got (1, 2, 3, ?) and (2, 4, 6, ?) easily. She did them in her head, but she was stumped by (3, 6, 9, ?). I told her to use the abacus. The first line has 3 beads, the second 6, the third 9. The concrete and visual representation made it suddenly clear, "It goes up by 3!" Then we went up to 30 counting by 3. Some times a little bit of connection with real life helps a lot!