Time spent = end time-start time,
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, the available result is that Xiao Ming needs 50 minutes from home to school.
Extended data
1, vertical calculation refers to a vertical calculation in the calculation process, which makes the calculation simple. In addition calculation, the same numbers are aligned. If the sum exceeds 10, it will move forward to 1. When subtracting, the same numbers are aligned. If it is not enough, borrow 1 from the last digit as 10. When converting to other non-decimal vertical calculation, it can be converted according to the specific internal conversion relationship.
2. The relationship between conversion time is as follows:
1 hr = 60min min (m) = 3600s.
3. The origin of "hour" is as follows:
In ancient China, time was measured by the method of "dripping water from a copper pot", and day and night were divided into twelve hours. One hour is equivalent to two hours of western clocks. When clocks and watches were introduced to China from the west, people called an hour "striking time" in China and a new hour "striking time" in the west. Later, with the popularity of clocks and watches, the word "Da Shi" gradually disappeared, and "Shi" has been used to this day.
References:
Baidu Encyclopedia: Vertical Computing
Baidu Encyclopedia: Hours