Help me please! Math Fractions problem

[Yuliroshi]

Tina wanted to find a common denominator and equivalent fractions for ⅗ and ⅔. This is what she did: Was Tina correct? If not what was her error? Draw diagrams to show what Tina should have done. Then theres 2 pictures One of them is a square with 15 sections in total and 3 colored and the other is another square with 15 sections but 2 colored

 

[tkhunny]

No, that sounds oddly odd.

1) 3/5 is not the same as 3/15. Likewise 2/3 is not the same as 2/15.

2) Where did 15 come from? What would "Tina" have done with 2/5 and 3/10?

 

[HallsofIvy]

What Tina should have done was draw a square with 5 sections, 3 of them colored, representing the fraction 3/5, draw a square with 3 sections, 2 of them colored representing the fraction 2/3. Then, to represent "common denominators" divide each of the 5 sections into 3 so she now has 15 sections there, but with 9 of them colored, and divide each of the three sections into 5 so she now has 15 section, 10 of them colored. She now has 9/15+ 10/15= 19/15.