23:4:5-1

It looks like you're presenting a mathematical expression. However, the format isn't entirely clear. If you mean to simplify or evaluate the expression \( 23:4:5 - 1 \), we first need to interpret the ":" symbol.

1. If ":" refers to a division, the expression could be interpreted as: \[ \frac{23}{4} \div 5 - 1 \]

2. If you intend to carry out the operations in order, we would calculate: \[ \frac{23}{4} = 5.75 \] Then divide by 5: \[ 5.75 \div 5 = 1.15 \] Finally, subtracting 1: \[ 1.15 - 1 = 0.15 \]

If you meant something else with "23:4:5-1," please clarify so I can assist you better!