Molly looked at Bertie after she'd played a bit. He seemed to be smiling, that meant she hadn't been too bad. She never was good at knowing how good she was at things. She knew she was good at Quidditch, because they let her on the team, and magical creatures seemed to like her. Molly was a bit unsure of herself, always needed a ton of confirmation to admit she was good at anything.
She picked up the piece of parchment Bertie had written the notes on, and balanced it on the holder-thing on the front of the piano. She assumed it was meant to hold music, but actually had no idea. It seemed to work though. As he was going to get another instrument, which he called a 'flute', she went through the notes one more time.
"Three, two, one, two, three, three, three, two, two, two, three, five, five, three, two, one, two, three, three, three, two, two, three, two, one." she sang the notes off of the piece of paper, managing to get the right notes on the piano purely because she never had to move her fingers off the appropriate keys. Molly was happy she did it though. Her singing was near note perfect, though she was paying more attention to the piano.
"Hey, it worked! I mean, I did it." she exclaimed to Bertie, happily, now eager to try it with him on the other instrument. "We can try it together now, right?" she asked him, her hand at the ready on the keys.