(4:7)-1+45

To solve the expression \( (4:7) - 1 + 45 \), let's first clarify what \( 4:7 \) means. It's often interpreted as a fraction, which is \( \frac{4}{7} \).

Now let's rewrite the expression:

\[ \frac{4}{7} - 1 + 45 \]

Next, we need to convert \( 1 \) into a fraction with the same denominator:

\[ \frac{4}{7} - \frac{7}{7} + 45 \]

This simplifies to:

\[ \left(\frac{4 - 7}{7}\right) + 45 = \frac{-3}{7} + 45 \]

Next, to add \( 45 \), convert \( 45 \) into a fraction with the same denominator:

\[ 45 = \frac{315}{7} \]

Now we can combine the fractions:

\[ \frac{-3}{7} + \frac{315}{7} = \frac{-3 + 315}{7} = \frac{312}{7} \]

Thus, the final answer is:

\[ \frac{312}{7} \]

If you want a mixed number, this equals:

\[ 44 \frac{4}{7} \]

So, the result of \( (4:7) - 1 + 45 \) is either \( \frac{312}{7} \) or \( 44 \frac{4}{7} \).