For example, Xiaoming left home at 7: 30 in the morning and arrived at school at 8: 20. How long does it take Xiaoming to get from home to school?

As the title says, the end time is 8:20 and the start time is 7:30. Therefore, it can be listed as follows:

As can be seen from the formula, there is not enough time on the minute bit, so we need to borrow one bit forward, and one hour is equal to 60 minutes. The process is as follows:

After borrowing, the formula is as follows:

Therefore, it can be concluded that it takes Xiao Ming 50 minutes to get from home to school.

The calculation of extended data time is divided into calculation time: the unified timing method adopts tail+head method.

Expression: When and when?

Calculation period: unified timing method adopts head-to-tail calculation.

Means: hours and minutes.

Different representations represent different results.

For example:

Time after 9: 00 am 15 minutes (calculation time): 9: 00 am 15 (9: 15).

How long does it take from 9:00 am to 10:30 am (time period): 1 hour 30 minutes.