How many hours in a day? How many hours in 2 days? how many days in 6 weeks? how many days in 12 weeks? how many days in 12 weeks and 4 days? how many days in 3 weeks?

$$
1 \text{ day} = 24 \text{ hours}
$$
The number of hours in a day is 24.
$$
\boxed{\text{24 hours}}
$$

$$
2 \text{ days} \times 24 \frac{\text{hours}}{\text{day}} = 48 \text{ hours}
$$
$$
\boxed{\text{48 hours}}
$$

$$
6 \text{ weeks} \times 7 \frac{\text{days}}{\text{week}} = 42 \text{ days}
$$
$$
\boxed{\text{42 days}}
$$

$$
12 \text{ weeks} \times 7 \frac{\text{days}}{\text{week}} = 84 \text{ days}
$$
$$
\boxed{\text{84 days}}
$$

$$
12 \text{ weeks} \times 7 \frac{\text{days}}{\text{week}} = 84 \text{ days}
$$

$$
84 \text{ days} + 4 \text{ days} = 88 \text{ days}
$$
$$
\boxed{\text{88 days}}
$$

$$
3 \text{ weeks} \times 7 \frac{\text{days}}{\text{week}} = 21 \text{ days}
$$
$$
\boxed{\text{21 days}}
$$