Most Popular Articles
Time Calculations with a Calculator
Adding and subtracting time is often a complicated task. Addition isn't impossible, because the minutes and seconds can be added in their places, and then the seconds that exceed 59 can be reduced and converted to minutes. Subtraction can be much more tedious.
A simpler method is to apply the 940 rule. Here's how it works.
Take the time amounts and replace the colon separating the hours and minutes and replace it with a zero. For example, one minute and thirty seconds (1:30) becomes 1030. Add the various times in this converted format. When the final sum is determined, add 940 to it, then reconvert the zeroes back to colons to reveal the result.
Here's an example. Add 1:24, 2:12, 5:50 and 6:03.
Add 940 to the result
Replace the zero with a colon and the result is 15:29.
Subtraction works the same way. Subtract 2:50 from 6:03.
Replace the zero with a colon to get 3:13.
Adding several times that are close to a full minute will not work properly with this approach. For example, 1:59 + 1:59 + 1:59. (Try it and you'll see the problem.) If you find an odd result with more than two addends, add the amounts separately. In this case, add 1059 + 1059 = 2118 + 940 = 3058. Then add 3058 + 1059 = 4117 + 940 = 5057.
If you don't want to keep splitting your addends, you can also use the commutative property of addition. If you add multiple times plus a single 940 and get a result that does not include a zero to convert to a colon, keep adding 940 until the result provides a number that can be converted back to a time. For example: 1059 + 1059 + 1059 + 1050 + 940 + 940 + 940 = 7047.
Acceptable Use Policy blog comments powered by Disqus
[an error occurred while processing this directive]
Today in Radio History
The history of radio broadcasting extends beyond the work of a few famous inventors.
Read each issue online in our Digital Edition Format in your Web browser.
EAS Information More on EAS
The feed provides feeds for all US states and territories.
Need a calendar for your computer desktop? Use one of ours.
Information from manufacturers and associations about industry news, products, technology and business announcements.
When Northern Community Radio set out to build a new community radio station in rural northern Minnesota 38 years ago, naysayers said that it would be broadcasting “only to a bunch of gophers
Browse Back Issues[an error occurred while processing this directive]
Also in the July Issue
- Trends in Technology: Robust IP STL
- LPFM on The March
- RF Engineering: Modern Modulation Techniques
- Field Report: Tascam TH-2000 Headphones
- Battery Maintenance: Testing and Charging