Matthew was referring to the songs we sang the previous day. We figured this out just by the songs that he was telling us about. All of them were the ones that we had sung with him. He had kept track of every song that we sang. He numbered each song according to the order in which we sang it.
Autistic children have many special skills.
They love music and they love to sing. Autistic kids are also generally good with numbers. Matthew was very smart when it came to using numbers. He could memorize anyone's birthday. He asked me when my birthday was the first day I met him, and he still knew it on the last day of camp.