Chrissy Teigen Celebrates Husband John Legend's 42nd Birthday by Hosting 'Math-Off' Game Show

Chrissy Teigen/Instagram

The limit does not exist for John Legend's birthday celebrations!

On Monday, the musician's wife, Chrissy Teigen, celebrated his 42nd birthday by hosting a "math-off" game show between Legend and their director/photographer friend, Mike Rosenthal, while on vacation with her family in St. Barts.

For the birthday event, Teigen fully committed to the hosting role wearing a sequined red gown and holding a sparkly silver microphone. The Cravings cookbook author also twined with good friend and Rosenthal's wife, celebrity hairstylist Jen Atkin, for the occasion.

As the Jeopardy! theme music played in the background, Teigen, 35, told the camera in the first of a series of videos on her Instagram Story, "For John's birthday, we created the ultimate math-off competition. John and Mike love doing math."

"To all of you at home, I just want to let you know, this is sixth-grade math. They have a 40-question math test in their hands. There will be bonus questions throughout the game," added the model.

Chrissy Teigen/Instagram

Chrissy Teigen/Instagram

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As Legend and Rosenthal, 43, set off on "competing for the title of math-off champion" — dressed in stereotypical "nerd" outfits, complete with taped glasses — Legend admitted, "All the fractions and the exponents, I do not remember how to treat them."

But his hesitance over certain parts of the test proved to be no big deal, as he was soon shown holding the winner's trophy with a big smile on his face.

"John, can I have one interview? How does it feel?" Teigen asked her husband, who hilariously responded, "I feel like I might get laid tonight."

One problem? The first-place trophy bore Rosenthal's name. But the runner-up made a quick fix, using a Sharpie to change "1ST PLACE" to "2ND."

Chrissy Teigen/Instagram

Chrissy Teigen/Instagram

RELATED VIDEO: John Legend Says He's Most "Thankful" for Chrissy Teigen This Year: "She's Been So Courageous"

John Legend Says He's Most 'Thankful' for Chrissy Teigen This Year: 'She's Been So Courageous'

On Tuesday morning, the couple announced they are partnering with McDonald's to help give back to other families with critically ill or injured children through Ronald McDonald House Charities

The lighthearted celebration comes after a difficult past few months for the couple, who lost their son Jack after 20 weeks of pregnancy in September. (Legend and Teigen are also parents to son Miles, 2, and daughter Luna, 4.)

Teigen shared a photograph of herself on Instagram last week, where she candidly spoke about her body, mourning that she will never be pregnant again following the loss of her son.

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"This is me and my body, just yesterday. Even though I'm no longer pregnant, every glance in the mirror reminds me of what could have been," the Lip Sync Battle host wrote. "And I have no idea why I still have this bump, honestly. It's frustrating."

Then, noting that she is "proud of where this entire journey took my body and mind in other ways," Teigen added, "I love being pregnant, so so much, and I'm sad I never will be again."

"But I am lucky to have two amazing little ones who are transforming into big little people more and more every single day," she said.