Probably not that many. Let's say you create a water-skipping robot with two different AI programs in it and a shaky, not very precise arm (but still as good as a human arm in terms of specs).
One is custom-made to the physics of the problem, and will calculate the angles and the forces and the pressures and the candy tasty physekz all over, and then decide on a particular motion of the robot arm, and the rock will skip. It'll take a lot of computing power, but it'll work.
The other just has a goal, to see the rock skip, and tries things at semi-random (though it has the general knowledge that it can be done and that it has to throw the rock towards the water in a particular way for it to happen and that it can control the outcome), and tries to figure out patterns between what it did and what happened as a result. Eventually, it has a particular tactic, a certain set of instructions, which could be "down down down the left thing and up up right down down the right thing and the up thing does down down up push push down push twist-force-2 at the same time", an entirely not at all complicated set of instructions with very little computation. This signal is sent through other nodes that might not have the perfect signal number, and eventually this outputs to the arm's motors... which nevertheless manage to make the rock skip, because the motion here is almost the same as the motion of the first AI, yet this one was obtained by eliminating the ones that didn't result in the rock skipping.
TL;DR: You don't do that many calculations on the spot. The "maths" in most situations like this is done by elimination throughout all the attempts you've made in your life to control a throw. Subsequent throws once you're already a practiced rock-skipper just involve firing "the same neurons as usual" which send "the same signals as usual" to your muscles, which result in the same skipping as usual, with very little math. If you already know that 2x^5 + 20 = 110 implies x = 45 from doing the same calculation twenty times in the past hour, your brain isn't performing "calculations" anymore, it's just repeating a pattern that's already there in your brain like a table lookup.
Probably not that many. Let's say you create a water-skipping robot with two different AI programs in it and a shaky, not very precise arm (but still as good as a human arm in terms of specs).
One is custom-made to the physics of the problem, and will calculate the angles and the forces and the pressures and the candy tasty physekz all over, and then decide on a particular motion of the robot arm, and the rock will skip. It'll take a lot of computing power, but it'll work.
The other just has a goal, to see the rock skip, and tries things at semi-random (though it has the general knowledge that it can be done and that it has to throw the rock towards the water in a particular way for it to happen and that it can control the outcome), and tries to figure out patterns between what it did and what happened as a result. Eventually, it has a particular tactic, a certain set of instructions, which could be "down down down the left thing and up up right down down the right thing and the up thing does down down up push push down push twist-force-2 at the same time", an entirely not at all complicated set of instructions with very little computation. This signal is sent through other nodes that might not have the perfect signal number, and eventually this outputs to the arm's motors... which nevertheless manage to make the rock skip, because the motion here is almost the same as the motion of the first AI, yet this one was obtained by eliminating the ones that didn't result in the rock skipping.
TL;DR: You don't do that many calculations on the spot. The "maths" in most situations like this is done by elimination throughout all the attempts you've made in your life to control a throw. Subsequent throws once you're already a practiced rock-skipper just involve firing "the same neurons as usual" which send "the same signals as usual" to your muscles, which result in the same skipping as usual, with very little math. If you already know that 2x^5 + 20 = 110 implies x = 45 from doing the same calculation twenty times in the past hour, your brain isn't performing "calculations" anymore, it's just repeating a pattern that's already there in your brain like a table lookup.