Tick-Tick-Tick - Duration and Elapsed Time

The Clock Face: A clock is a circular tool with $12$ numbers written around its edge. It has three hands: the short 'Hour Hand', the long 'Minute Hand', and the thin, fast-moving 'Seconds Hand'. The distance between any two numbers on the clock represents $5$ minutes for the minute hand and $1$ hour for the hour hand.

Units of Time: Time is measured in units like seconds, minutes, and hours. $1 \\text{ hour}$ consists of $60 \\text{ minutes}$, and $1 \\text{ minute}$ consists of $60 \\text{ seconds}$. To convert hours into minutes, we multiply the number of hours by $60$. For example, $3 \\text{ hours}$ is $3 \\times 60 = 180 \\text{ minutes}$.

AM and PM: A full day has $24$ hours, divided into two halves of $12$ hours each. 'AM' (Ante Meridiem) starts from $12 \\text{ midnight}$ and goes until $12 \\text{ noon}$. 'PM' (Post Meridiem) starts from $12 \\text{ noon}$ and goes until $12 \\text{ midnight}$. $12:00$ during the day is called 'Noon' and $12:00$ at night is called 'Midnight'.

The 24-Hour Clock: This system, often used in railways, uses numbers from $00:00$ to $23:59$. To convert PM time to 24-hour format, we add $12$ to the hours (for example, $2:00$ PM becomes $14:00$). To convert 24-hour time back to PM, we subtract $12$ from the hours.

Elapsed Time (Duration): This is the total time that passes during an activity. To calculate duration, we subtract the 'Start Time' from the 'End Time'. If the duration spans across AM and PM, it is helpful to convert both to the 24-hour format first ($Duration = \\text{End Time} - \\text{Start Time}$).

Calendar and Months: A year has $12$ months. Some months have $31$ days (January, March, May, July, August, October, December) and others have $30$ days (April, June, September, November). You can use the 'knuckle rule'—where knuckles represent $31$-day months and the gaps between them represent $30$-day months—to remember these lengths.

Leap Year: A standard year has $365$ days. A leap year occurs every $4$ years and has $366$ days because February has $29$ days instead of $28$. If a year is divisible by $4$ (like $2024$), it is usually a leap year.

Date Formats: Dates are commonly written in the $DD/MM/YYYY$ format. For instance, the 10th of July 2023 is written as $10/07/2023$. The first two digits are the day, the next two are the month number, and the last four are the year.