What kind of pleasure is the one we get by pursuing Mathematical problems and solving them? Is it a kind of sensual pleasure?
I think it would be classed as household joy;

&quot;And what are the six kinds of household joy? The joy that arises when one regards as an acquisition the acquisition of forms cognizable by the eye — agreeable, pleasing, charming, endearing, connected with worldly baits — or when one recalls the previous acquisition of such forms after they have passed, ceased, &amp; changed: That is called household joy. (Similarly with sounds, smells, tastes, tactile sensations, &amp; ideas.)

The other types of joy are tied up with renunciation;

&quot;And what are the six kinds of renunciation joy? The joy that arises when — experiencing the inconstancy of those very forms, their change, fading, &amp; cessation — one sees with right discernment as it actually is that all forms, past or present, are inconstant, stressful, subject to change: That is called renunciation joy. (Similarly with sounds, smells, tastes, tactile sensations, &amp; ideas.) MN137

One like this thinks; i am good because of this [solving], delights in thinking, dwells in solving, neglects seclusion and does not attend to the teacher's message.
I think it's like entertainment, a hobby or a sport.