(56+23)-12:3

To solve the expression \( (56 + 23) - 12:3 \), we start with the operations inside the parentheses, followed by subtraction and division.

1. Calculate \( 56 + 23 \): \[ 56 + 23 = 79 \]

2. Now we have \( 79 - 12 : 3 \). The colon in mathematical expressions is often used to denote division, so \( 12 : 3 \) means \( 12 \div 3 \).

3. Calculate \( 12 \div 3 \): \[ 12 \div 3 = 4 \]

4. Now substitute that value back into the expression: \[ 79 - 4 \]

5. Finally, perform the subtraction: \[ 79 - 4 = 75 \]

So, \( (56 + 23) - 12:3 = 75 \).