A: 333
The clocks in the first row represent 9 + 9 + 3
The calculators in the second row are each 10 (also 1234 added together is 10)
Each lightbulb in the third row is 15 (15 + 15 – 15) = 15.
Which means each ray above the lightbulb =3
So in the last row:
9 + 9 x (12 + 12 + 12)
9 + 9(36)
9 + 324
333
10/31/20 update from Colin Porteus — thanks for your sharp eyes!!
Hello Robin, can you check the last row on this one please? I get 9 + 9 x (12 + 16+ 16)?? The bottom two globes have 4 threads each x the 4 light marks makes them 16 each?? So consequently I get a result of 405.
Thank you
Math Confidence by Robin the Math Lady 
Hello Robin, can you check the last row on this one please? I get 9 + 9 x (12 + 16+ 16)?? The bottom two globes have 4 threads each x the 4 light marks makes them 16 each?? So consequently I get a result of 405.
Thank you
Colin
Hi Colin Sorry for taking so long to reply.
I definitely need my granny glasses to see the details!
The photo is not the best quality and those lightbulbs do indeed look like they are longer. Thanks for spotting this!
Very Sincerely,
Robin
Hi Robin, can you check the last row on this one please??
I don’t agree that the bulb in 3rd raw is Valuing 15 ( 3 threads × 5 light marks)
I suggest. I thread = 2.5 and 1 light mark = 1.5
So 2.5× 3 + 1.5×5 = 15
The bottom two globes have 4 threads each x the 4 light marks makes them( 2.5×4+ 1.5×4)= 16 each?? and One bulb with 3 threads is ( 1.5×4 +2.5×3)= 13.5
So the Last raw is
9 +9× ( 16+16+13.5)= 418.5
consequently I get a result of 405.
Thank you