JP; If you're firm about remaining a "recreational" one-or-twice a month player at say, $5-to-$50 or $10-to-$90 spreads, then I wouldn't recommend a full blown system like HI/LO.
You mentioned being good in math, so a recreational level "plus/minus" system may fit your wants/needs -- or easier yet (but less potent) are two simpler non-plus/minus counts.
The absolutely simplest method anywhere is the Ace/10 Front Count. No plus/minusing (just tallying up the Ace/10's together) and NO counting beyond the first two decks of the shoe. This is truly a "bare-bones", marginally positive recreational system. Source: Blackjack Bluebook II; $16.50
Next above that is Scoblete's Speed Count. Not exactly a plus/minus either, but adds up the 2's thru 6's and subtracts that from the number of hands at the table. Thus, it infers whether the number of played low cards has been light, normal or heavy at any given point. There's less error with this system in the shoe game than in single or double deck. It's modestly stronger and tougher to learn than the Ace/10 Front count. Source: Golden Touch Blackjack Revolution; $24.95
The first level of plus/minus counting systems is the unbalanced KISS Count. It's actually a family of three upgradable counts -- entry level, intermediate and full scale. The entry level (KISS I) pits just the "paints" (Jacks, Queens and Kings) against the 4's, 5's and 6's, along with the black deuces for unbalancing purposes. You can upgrade to KISS II later by simply adding the 3 on the low side and the 10-spot on the high side to your count structure. The full scale KISS III then adds the 7 on the low side and the Ace on the high side to its count structure. It comes with a beginner list of 6 deviations from basic strategy all activated at the same modestly positive count -- and later, 21 individually indexed deviations that go just beyond the illustrious 18. Source: Blackjack Bluebook II; $16.50
All these systems are easier to learn than HI/LO -- and the KISS III performs on par with HI/LO, KO and Red 7.