It would have got it right if you got it to show its working.
That's the trick to doing computations with LLMs, the computation per token is constant so you want to split the computation over many tokens.
> I have 2 cats and 1 horse. How many legs do they have in total? show your working.
> If you have 2 cats and 1 horse, they would have a total of 10 legs. Cats typically have 4 legs, so 2 cats would have 2 x 4 = <<24=8>>8 legs. Horses have 4 legs, so 1 horse would have 1 x 4 = <<14=4>>4 legs. Together, the 2 cats and 1 horse would have 8 + 4 = <<8+4=12>>12 legs.