Math Skillz
A very non-controversial statement about Daniel Larson is that, to put it lightly, he is not the brightest bulb due to his intellectual disabilities. There are many ways that Daniel displays his intelligence, one of these being his math skills.
His money management skills are probably extremely hampered by his math skills, it being one of many reasons behind his gambling.
Basic math skillz
Basic math encompasses addition, subtraction, multiplication, division, . Daniel is somewhat competent with these, at least with the addition and subtraction.
In this clip, Daniel is able to at least manage simple addition, managing to decipher the complex problem of six plus six, figuring out it is "trelve".
Dealing with larger numbers is more difficult for him, however, as the image above shows. You could chalk it up to Daniel being bad with time management, but who knows. This clip provides us with more evidence that Daniel just doesn't know how many days, weeks, or months are in a year or each other.
In this clip, however, our great leader is unable to solve 4^2, and struggles with 4-2. It is unknown if his inability to do these questions is because Daniel cannot comprehend square roots, or because Daniel cannot comprehend 4.