1+2=4

Grandad was really mad at Aunt Jennifer today for taking apart something he worked two hours to create just yesterday. He was explaining this to Grandma over dinner:
"And Paul (Jennifer's Husband) can't lift that all by himself! It took four people last time to lift it." Grandad said, consumed by a furious passion.
"Four people? I hope you weren't one of those four because your doctor said no heavy lifting," Grandma said.
"Oh, I wasn't," said Grandad off-handedly.
"Who was?" Grandma asked.
"Oh well, Duncan," Grandad said indicating me stuffing my face with meat and peppers and walnuts and all that good stuff, "And two women who were helping."
"Who was the fourth?" Grandma asked. That was some keen calculation there. I probably couldn't do that so fast as I was busy eating.
"Hm. Let me think," Grandad said.
There was quite a long pause as Grandad thought.
"Oh well, I guess that was me," Grandad said after much deliberation.