The video was a "different" direction in the sense that it does not incorporate the heavy dance routines Beyoncé is known for,[1] and that it experiments with psychedelic visual effects as well as innovative lighting, which give the clip a cinematic feel.

The clip met with generally positive reception from music critics, who praised its aesthetic and sexual theme and claimed that it will be remembered as one of Beyoncé's most iconic visuals.

[4] Lee Blaske, Nikki Gallespi and Pete Wolford played the instruments, while Brian Thomas alongside Pat Thrall assisted in recording the music.

[7][9][10] The song features "a soft, almost non-existent" backing beat[11] and makes use of a guitar and a piano as its foundation,[10][12] while wind chimes, sprinkling strings, synthesizers,[13] funk-influenced bass and a pipe organ are also present.

"[17] Nadine Cheung wrote that the subtle instrumentation allows Beyoncé'ss voice to emphasise the emotional lyrics[18] Amos Barshad of New York magazine and Tim Finney of Pitchfork Media described the vocals as similar to those of Whitney Houston's work.

[20] Brandon Soderberg of Pitchfork explained that "Wonderful World"'s line, "don't know much about algebra", was retained during the conception of "1+1" by its producers, who however accentuated its "love song sentiment".

[21] Soderberg further wrote that "1+1" bears resemblance to "Purple Rain" as they both have similar "delicate guitars, melodramatic piano, and [Beyoncé affects Prince's] high-register whimper a few times".

[10] Using simple arithmetic to describe her undying love for her partner,[12][22] she begins the first verse as she affirms to her romantic interest that the only thing she is sure about are her feelings for him,[18][22] "I don't know much about algebra, but I know that one plus one equals two ...

[6][26] "1+1" was lauded by music critics, who complimented the effective display of Beyoncé's emotive vocals due to the use of light instrumentation, and approved that the ballad was the opening song on 4.

"[22] Matthew Perpetua of Rolling Stone wrote that "the album [4] opens with its most tender ballad, a slow-burning number that calls back to both Sam Cooke's 'Wonderful World' and Prince's 'Purple Rain' without sounding like a retread of either tune [...] it sounds best in the context of the album, where its slow, steady build to a cathartic guitar break is the perfect introduction to a set of mostly low-key tracks about love and heartbreak.

"[20] Similarly considering "1+1" to be "the perfect opener" of 4, Joanne Dorken of MTV UK wrote that it exposes a more vulnerable side of Beyoncé and that it will remain "a classic stripped-back slow jam from the diva.

"[30] Cameron Adams of the Herald Sun wrote that "1+1" is an "amazing [and] arguably the most honest and tender Beyoncé has sounded, singing 'help me let my guard down, make love to me'".

[19] Andy Kellman of Allmusic picked "1+1" as one of the album's top songs, describing it as "a sparse and placid vocal showcase, [which] fades in with a somber guitar line, throws up occasional and brief spikes in energy, and slowly recedes.

"[33] Chris Coplan of Consequence of Sound commented that in contrast to the geometry taught at school, there is something interesting in "1+1"; he further wrote that ballad focuses on Beyoncé's "amazing vocal range" as it is not upbeat like most of her previous offerings.

[39] The staff members of Pitchfork placed the "1+1" at number 26 on their list of The Top 100 Tracks of 2011, writing: Following Beyoncé's work on "1+1" is like a journey to the center of her craft, a stripping away of every distraction until all that's left is her voice.

Without it, "1+1" would be a muted ballad: Its simple guitar line and stardust-sprinkled strings serve no purpose other than to evoke a sense of familiar romantic intimacy, and then to elegantly step aside while Beyoncé delivers one of her most wonderfully impassioned performances ever.

Beyoncé is R&B's field marshal, demanding of her listeners and herself an absolute fidelity to the music's emotional possibilities, with a perfectly modulated vehemence that is as captivating as it is tyrannical.

[41] Writing for The New Yorker, Jody Rosen credited the jarring timbral and tonal variations on the song for giving a new musical sound that didn't exist in the world before Beyoncé.

A quick shot of the "IV" tattoo inked on Beyoncé's left ring finger is shown (a reference to her album's title, 4),[58] before she bathes in a tub of flowers as well as berries and blows billows of smoke.

News found the video "sexy" and "pretty stripped down", further writing: "There are no catchy choreographed dances or freakum dresses, just Queen Bey looking gorgeous in lingerie and belting out her love and devotion to her man."

[59] Tanner Stransky of Entertainment Weekly concluded that although the video was different from the previous "heavily produced spectacles" Beyoncé has made, "it's hard to take your eyes off it".

[62] Similarly, Willa Paskin of New York magazine praised the final minute of the video in which "we are treated to what is supposed to be the instrumental equivalent of an orgasm", illustrated by split-screen kaleidoscope effects and capped off by Beyoncé staring into the camera "in postcoital contentment".

[63] She compared the kaleidoscope effects with Lady Gaga's "Born This Way" (2011) and finished her review by writing, "ultimately, the clip shows the diva doesn't need the elaborate costumes, club-anthem rhythms and booty-quivering grooves to bring the heat.

[67] Rob Markman of MTV News wrote that the choreography is very different from the Beyoncé's standard dance routines, which feature high-powered steps, swaying hips and "her patented bootylicious shake".

"[1] Markman added that the video will most likely remain "under the radar" in comparison to the highlights in her high-budgeted reel, which includes clips like "Single Ladies (Put a Ring on It)" (2008) and "Crazy in Love" (2003).

The video has a similar impromptu charm to the many intimate, one-shot performance clips popularized by Vincent Moon's Take-Away Shows, its appeal compounded by the shock of seeing such a notoriously manicured superstar without embellishment.

"[79] Mike Wass of Idolator praised how Beyoncé "wrung every ounce of emotion from the lyrics of '1+1' and hit each note perfectly", concluding that it was "an impressive display.

"[80] Entertainment Weekly's Brad Wete wrote that Beyoncé's voice "rang soulfully, only breaking to let the crowd fill in gaps for a sing-along feel.

[85][86] Jim Farber of Daily News commented that the song was sung with "precision and sweep, she tipped the balance decidedly softer, giving her power grounding".

[97] Beyoncé appeared on Entertainment Tonight on June 16, 2011, to promote the exclusive-to-Target deluxe edition of 4 and gave fans a sneak preview of its television commercial.