## Ask an Expert

## How do I know what changes California made to the national version of the Common Core?

Thanks to Felicity from Los Angeles for the question. The changes are fairly minimal, but it’s important to know what they are. Click here for California’s version of the standards. Standards unique to California are in bold and have “CA” written after the standard. For example, on page 129, two function standards have been added under “Interpreting […]

See Answer## Are there more fractions or decimals?

Thanks to Anonymous 9th Grade Student for the question. This is actually a surprisingly deep question. When students are in elementary school, they are taught how to convert between the decimal and fractional representations of a number. 0.4 = 2/5. 0.33333333333…=1/3. 0.237 = 237/1000. So we might initially think that every decimal can be written […]

See Answer## Are there any practical applications of pi, aside from calculating the area or circumference of a circle?

Thank you to Linda Johnson from Walnut Creek for the question. Dr. David H. Bailey, co-discoverer of the Bailey–Borwein–Plouffe formula for pi, guest authored this post. Many presume that π is only used for geometric measurements, say to calculate the area of circle or its circumference. While such calculations are done many, many times every […]

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