Obama -- FIELD TRIP WITH THE PREZ!!

10:50 AM PT -- The bill came to $100 and we're told Obama tipped 30%. You can do the math.

President Obama escaped the White House with 5 young people ... and they hit up a very cool, neighborhood burger joint with almost no advanced notice.

The 5 young people are all working on the Affordable Care Act.

At the time we posted this, they were all still at The Coupe in Columbia Heights.

We're told Obama is enjoying a Coupe Burger -- "Our classic with fried onion rings, sauteed mushrooms and sharp cheddar. And get this ... we were told fries, but turns out the side is spinach.

We're told the restaurant got "vague word" yesterday the Prez might be showing up sometime soon, but there was no advanced interior sweep of the place ... they just showed up a short while ago.

In case you're wondering ... here's the menu.