403-654:3+398*2

To evaluate the expression 403-654:3+398*2, we need to follow the order of operations, also known as PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction):

First, we perform any calculations within parentheses or brackets. However, since there are no parentheses in the expression, we move to the next step.

Next, we evaluate exponents. There are no exponents in the expression.

Then, we perform any multiplication and division from left to right.

So, we start with 398*2 = 796.

Next, we perform addition and subtraction from left to right.

403 - 654 = -251. Then, we have -251 divided by 3 = -83.66666667 (rounded to 8 decimal places).

Finally, we add the result of the division to the previous multiplication: -83.66666667 + 796 = 712.33333333 (rounded to 8 decimal places).

Therefore, the value of the expression 403-654:3+398*2 is approximately 712.33333333.