7 -4+3x0+ 1 = ?
is this BEDMAS... (Brackets, Exponents, Division, Multiplication, Addition, Subtraction)
you just Multiply 3x0=0 then you Add 4+0+1=5 then you Subtract 7-5 = 2
7-4=3 +1=4 ??
The different answers come from the fact that in the first question, the OP has forgotten that everything needs to be subtracted from 7.
The answer is 4. Your method in the first case is correct, but you have forgotten that since addition and subtraction have equal power, that once you have nothing but additions and subtractions left, that you work from left to right.