### Instruction: Find $1+2\cdot3-4+5.$.### Response: To simplify this expression, I need to follow the order of operations, which is parentheses, exponents, multiplication and division, and addition and subtraction.
There are no parentheses or exponents in this expression, so I can skip those steps.
Next, I look for any multiplication or division. I see that there is a 2 times 3, so I do that first and replace it with 6.
The expression becomes $1+6-4+5.$
Now, I only have addition and subtraction left, so I can do them from left to right.
First, I add 1 and 6 and get 7. Then I subtract 4 from 7 and get 3. Finally, I add 5 to 3 and get 8.
The expression simplifies to 8.