Equal-Chan and Integral-San (the latter appears to be pudgy, I had to) alongside a background with equal cards, alongside ones that read 314 26.

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things are getting pretty equal... once again, happy international day of mathematics! #LNLArt #MathPlay #イコールカードDS #MathPlayOC

and yes, that's rupineko as Integral-San on the right

Happy International Day of Mathematics!

It's crazy to think that many people got obsessed with Equal-Chan, the mascot of Math Play! #LNLArt #MathPlay #イコールカードDS #MathPlayOC #イコールカードOC