1

Brian brings 2 airplane tickets to Michael: 1 round trip, 1 one-way.

2

Walt turns 2 a week form when Michael is in the hospital, speaking to the nurse

Michael drew the picture of a penguin with sunglasses for Walt's 2nd birthday.

Susan hadn't heard from Michael in 2 months

Brian brings Michael 2 airplane tickets.

7

Michael drew 7 cake candles on the birthday card for Walt's 2nd birthday while he was laid up in the hospital.

21

Walt is 21 months old when Michael calls Susan, and is later hit by a car.

36 - 38 - 41

Numbers on Rousseau's maps that Sayid matches up to make up the triangle.