WASHINGTON (CNN)  -- President Obama on Monday gathered together every confirmed member of his Cabinet for the first time as president and challenged them to cut $100 million in the next 90 days. President Obama meets Monday with his Cabinet, including Defense Secretary Robert Gates, right. Agencies will have to report how they saved on expenses at the end of the period. The federal government has "a confidence gap when it comes to the American people," Obama said at the White House. "We've got to earn their trust. They've got to feel confident that their dollars are being spent wisely."
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NEW: President Obama says, "We've got to earn [the public's] trust"
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NEW: Obama meets with Cabinet to discuss how agencies can cuts costs
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Agencies will have to report how they saved on expenses after 90 days
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Critics say $100 million in savings is a small amount
"Only in @placeholder, is $100 million not a lot of money," Gibbs said.