Question

LXXIV Arabic numerals

Answer 1

L stands for 50
X for 10 (XX being 20)
IV is 4 (V stands for 5 and I for 1 and the fact to put I before V means substract 1 to 5 so 4)
So your number is 50+20+4 which is 74

Answer 2

Isn't that Roman Numerals? But anyways,

L = 50

X = 10

X = 10

IV = 4.

So, 50 + 10 + 10 + 4 = 74.

The answer to your question is 74.