The general rule of solving an expression is as follows:
B - Bracket
O - Of
D - Division
M - Multiplication
A - Addition
S - Subtraction
Also bar is the same as bracket, i.e. bar on top of x+y is the same as (x+y).
In the given question, since bar is on top of the entire expression, it has no significance since it just says that the entire expression has to be evaluated.
Now (23456 x 67) + 67 - 90 = 1571552 + 67 - 90 = 1571619 - 90 = 1571529