Leah spent 28 / 7 = $<<28/7=4>>4 on a milkshake.
She had 28 - 4 = $<<28-4=24>>24 left.
She put half in her savings account and half in her wallet, so she had 24 / 2 = $<<24/2=12>>12 in her wallet.
Her dog shredded all the money in her wallet but $1, so Leah lost 12 - 1 = $<<12-1=11>>11.
#### 11