Sen. Elizabeth Warren on Wednesday invited billionaire Bill Gates to meet so she could allay his worries about her plans to raise taxes on the wealthy and explain “exactly how much” he would pay.

Speaking with columnist Andrew Ross Sorkin at The New York Times DealBook Conference on Wednesday, Gates, the Microsoft co-founder and philanthropist whose fortune totals over $100 billion, said that he had paid over $10 billion in taxes and that it would be “fine” if he had to pay $20 billion.

“But, you know, when you say I should pay $100 billion, OK, then I’m starting to do a little math about what I have left over,” he added. “Sorry, I’m just kidding. So you really want the incentive system to be there, and you can go a long ways without threatening that.”

Sorkin then asked Gates if he had ever spoken about this with Warren — he said he had not — and asked Gates if he would want to.

“You know, I’m not sure how open-minded she is or that she’d even be willing to sit down with somebody, you know, who has large amounts of money,” Gates said.

Warren responded with a tweet Wednesday evening.

“I’m always happy to meet with people, even if we have different views,” she said, tagging Gates directly. “If we get the chance, I’d love to explain exactly how much you’d pay under my wealth tax. (I promise it’s not $100 billion.)”

For Warren, who has made battling corporate greed and corruption a central theme of her campaign and is now among the top contenders in the Democratic primary field, attacks from Wall Street and public clashes with billionaires have been welcomed as signs of her populist credibility and reformatory zeal.

Her proposals include a 2% tax on household net worth over $50 million. She outlined a plan last week to pay for “Medicare for All,” which calls for $20.5 trillion in new federal spending over a decade, by increasing her proposed wealth tax on net worth above $1 billion to 6% annually and raising taxes on investment gains for the top 1% of households.