Hanna has twice as many erasers as Rachel.  Rachel has three less than one-half as many erasers as Tanya has red erasers.  If Tanya has 20 erasers, and half of them are red, how many erasers does Hanna have?
How many red erasers does Tanya have? ** Half of Tanya's 20 erasers are red, so she has 20/2=<<20/2=10>>10 red erasers.
How many red erasers does Tanya have? ** One-half as many erasers as Tanya has red erasers is 10/2=<<10/2=5>>5 red erasers.
How many erasers does Rachel have? ** Rachel's three less than one-half as many erasers as Tanya's red erasers, which is 5-3=2 erasers.
How many erasers does Hanna have? ** Hanna has twice as many erasers as Rachel, for a total of 2*2=<<2*2=4>>4 erasers.
#### 4