1. The problem is to find the factor pairs of 4. 2. Factor pairs of a number are pairs of integers that multiply together to give the original number. 3. For 4, we look for all pairs $(a,b)$ such that $a \times b = 4$. 4. Start with 1: $1 \times 4 = 4$. 5. Next, 2: $2 \times 2 = 4$. 6. Since 3 does not multiply with an integer to give 4, we stop here. 7. Therefore, the factor pairs of 4 are $(1,4)$ and $(2,2)$.