Common denominators: 3/5 and 7/2  Math  4th grade  Khan Academy  Summary and Q&A
TL;DR
Learn how to convert fractions with denominators of 5 and 2 to a common denominator of 10.
Questions & Answers
Q: How can we convert fractions with denominators of 5 and 2 to tenths with a denominator of 10?
To convert, visually divide a whole into fifths or halves. Then, split each fifth or half into ten equal parts to represent tenths.
Q: What happens to the numerator when we change the denominator from 5 to 10?
When the denominator is doubled, as in the case of changing fifths to tenths, the numerator will also double because each shaded piece will split in two.
Q: Can you provide an example of converting 3/5 to tenths?
To convert 3/5 to tenths, divide the whole into fifths and shade three of those fifths. Then, split each fifth into tenths, resulting in six shaded tenths.
Q: How do we convert 7/2 to tenths?
To convert 7/2 to tenths, visually divide a whole into halves and shade seven of those halves. Next, split each half into five equal parts to represent tenths. The result is 35 shaded tenths.
Summary & Key Takeaways

To convert fractions, such as 3/5 and 7/2, to a common denominator of 10, visualize each fraction and divide the whole into equal parts.

Change the denominator by splitting each part in half or doubling the amount of pieces to achieve tenths.

The numerator will also change accordingly when the denominator is multiplied or divided.