2:3+4+68

If ":" means division (2/3):

• 2/3 + 4 + 68 = 2/3 + 72 = 218/3 ≈ 72.666...

So the exact result is 218/3, or about 72.67.

Note: treating 2:3 as the ratio 2:3 still yields the same numeric value 2/3 when turned into a number, so the result is the same. If you meant something else, please clarify.