DES MOINES, Iowa -- Viola Mourton buys a Powerball ticket every day. But with a $320 million jackpot that could grow in the next few days, she's upping her chances and buying several at her local convenience store.

"It's just a chance to win big money," the 51-year-old secretary from Ottumwa, Iowa, said Thursday. "I'll probably buy a couple today because it's so high. But it only takes one to win."

That could be the game plan for others around the country. No Powerball winner yet? No problem. That just means a bigger jackpot for the rest of us.

Lottery officials said no ticket matched all the numbers in Wednesday night's Powerball drawing. Three tickets won the $1 Million Match 5 prize. But it means the current $320 million jackpot could swell before the next drawing on Saturday.

The jackpot is the sixth highest in history, but it could grow depending on sales at the end of each day, said Mary Neubauer, spokeswoman for the Iowa Lottery, one of the founding Powerball states.