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Learning Target

Use stratigies to develope formulas for finding the circumferences

and diameters of circles.

Example

Multiply the diameter by π (pi) to get the circumference.

You have a can with the diameter of 14.7.

14.7 times π = 46.18  

The circumference of the can is 46.18.

Lesson

On Friday, we did an activity with the circumferences and diameters of circles.  We

took 5 circular objects, such as cans and buckets, and measured the circumferences

and diameters of them with a tape measure.  We found that the circumference divided 

by the diameter equals π.  With any circle, you can multiply the diameter by π to get the

circumference, or divide the circumference by the diameter to get π.  it is like a fact 

family.

Learn More

Visit a website to learn more about circumferences and diameters of circles.

 Thermal  Energy Link

Thermal Energy

Learning Target

Estimate sums and differences using decimals. 

Example

54.68 + 67.26

55.00 + 67.00 = 122.00

23.57 - 17.32

24.00 - 17.00 = 7.00

Lesson

To estimate sums or differences using decimals, always round to the nearest whole number.

To round, look at the tenths place in the decimal. If the number in the tenths place is 4 or

below, round down. If the number in the tenths place is 5 or above, round up. Then add or

subtract the rounded numbers.

Take a Quiz

See how much you know about adding and subtracting decimals by taking this quiz.