Answer: Eric still needs
of a deck.
Explanation:
You know that:
- Eric need 1/2 deck of playing cards.
- Eric has 2/7 of a deck.
Therefore, to find the fraction of a deck that Eric still needs, you must subtract 1/2 and 2/7:
- Find the least common multiple of the denominators:
![2=2*1\\7=7*1](https://img.qammunity.org/2020/formulas/mathematics/high-school/qw64riwdka175bn7d1qztc5znrcw4mwvzj.png)
![LCM=2*7*1=14](https://img.qammunity.org/2020/formulas/mathematics/high-school/32au3o5jr0sm6ngn2imn5vueh7x14xqkij.png)
- Now, you can make the subtraction:
![((7*1)-(2*2))/(14)=(7-4)/(14)=(3)/(14)](https://img.qammunity.org/2020/formulas/mathematics/high-school/8gtlmc24l34lrzx0bexe65euwdf51j7pci.png)
Therefore, he still needs
of a deck.