Right, let's decipher this:
The first two clocks are at 9, the third is on 3. 9 + 9 is 18, + 3 is 21.
The calculators show 1234. 1 + 2 is 3, +3 is 6, + 4 is 10. 10 + 10 +10 is 30.
One lightbulb + one lightbulb means two lightbulbs, - one lightbulb has one lightbulb left, equalling 15. So, one lightbulb = 15.
Now, keeping in mind to multiply before adding, let's solve the calculator x three lightbulbs first.
The calculator shows 1224 (as opposed to the 1234 in the earlier examples, rather nasty trick there), 1 + 2 is 3, +2 is 5, +4 is 9.
One lightbulb would be fifteen, if they had the same number of rays beaming from them. Where the earlier examples had five rays, these only have four. So, the earlier example did not actually mean one lightbulb = 15, but five rays = 15, so one ray = 3. Thus, each lightbulb with four rays is 12. Three lightbulbs of 12 is 36.
So, now we're at 9 x 36, which is 324. Adding the clock, which shows 9.
The final problem is 9 + 9 x 36 = 333.
Checking... and I'm right. Yay.