The What Works Clearinghouse has a number of evidence-based Practice Guides that focus on math practices that are associated with effective teaching. The Evidence Basis for Instructional Clip Art The Screen Reader will read the definition.Īpplications of Linear and Quadratic Functions Click on the PREVIEW button on the left and then click on the definition card.From the menu, click on the Screen Reader button.Click on the Accessibility icon on the upper-right part of the screen.To learn more about Slide Show Creator, click on this Link: Accessibility This resource can also be used with a screen reader. To see the complete clip art collection, click on this Link. Create a Slide Show Subscribers can use Slide Show Creator to create a slide show from the complete collection of math clip art on this topic. Related Resources To see additional resources on this topic, click on the Related Resources tab. The collection includes regular and digital clock faces. The downloadable image is part of a collection of clip art images showing clock faces in five-minute intervals. Try this with base 10 and you won't end up with as many, easy-to-remember fractions. With base 60, there are so many more fractional amounts of time that are whole numbers, and they're easy to remember. This table shows the fractions of an hour that result in whole number minutes of time that are easy to remember. Using base 10 with clocks would result in awkward fractions of time. The number 60 has many more factors, so we can measure time in fractions of 60 that are numbers that can be easily be remembered. Why 60? With time measurement, we want to keep precise track of the time. This is an example of counting in base 60.

After 60 minutes, the clock advances one hour and the minutes start again. Can you tell what the base is?Ĭlocks rely on a base 60 system. But with clocks there is a different number system at work. When we count from 1 to 10, we are using the base 10 system. Why are minutes and hours different? Why are minutes counted from 1 to 60? Why are hours counted from 1 to 12? We are so accustomed to counting objects from 1-10 and in multiples of 10. Why Are Hours Measured From 1-12 Not 1-10? Here are some sample times using the minute hand. The minute hand varies in value from 0 to 60. The minute hand is the longer of the two clock hands.

Here are some sample times using the hour hand. The hour hand varies in value from 1 to 12. It is the shorter of the two clock hands and looks like this.

There are additional tic marks between the main numbers.Look at the arrangement of numbers on the clock face. When you look at a clock, you can read the hour and the minutes. This pattern repeats for every hour and minute. The hour hand points to 1 and the minute hand points to 12. The hour hand is closer to 1 and the minute hand points to 9. The hour hand is between 12 and 1, and the minute hand points to 6. The hour hand is a bit past 12 and the minute hand points to 3. Both the hour and minute hands point to 12. Telling time involves reading both the hour and minute hand. Here is a tour of times around the clock in 5-minute increments. Here is a tour of times around the clock using the hour hand.

12 o clock clipart