Elapsed time

Japanese school year: Elementary 3

What you learn

You will learn how to determine elapsed time between two events and calculate future or past times. This is essential for planning daily schedules and estimating travel duration. A solid understanding of reading clocks and the relation that sixty minutes make an hour is helpful.

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Key points

This equation shows the relationship between days ( $\text{d}$ ) and hours ( $\text{h}$ ). One day equals $24$ hours, combining $12$ hours of a.m. and $12$ hours of p.m.

1 \text{d} = 24 \text{h}

This equation shows the relationship between hours ( $\text{h}$ ) and minutes ( $\text{min}$ ). Because $1$ hour is $60$ minutes, time calculations carry over to $1$ hour for every $60$ minutes.

1 \text{h} = 60 \text{min}

This equation shows the relationship between minutes ( $\text{min}$ ) and seconds ( $\text{s}$ ). Because $1$ minute is $60$ seconds, calculations carry over to $1$ minute for every $60$ seconds.

1 \text{min} = 60 \text{s}

This formula calculates elapsed time ( $\Delta t$ ). It is obtained by subtracting the start time $t_1$ from the end time $t_2$ .

t_2 - t_1 = \Delta t

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Practice 1Coming soon