(Suppose there is a calculation problem of 15( 1+2). If you use your method, it must be 15+ 15/2=45/2. In fact, the correct method is to calculate 1+2=3 in brackets first.
Seconds 25x1/8x4x4/5x8x5/4 = 25x4x1/8x8x4/5x5/4 =100x/x1=100? You are still wrong. 1 and 1/4 are 5/4, not 6/4.
The third result is -5/4, which means-1 and 1/4? You did the right thing.
The fourth-16-16x (-1)+9 = 0+9 = 9? You did the right thing.
The fifth -3-2+9=4? You did the right thing.
The sixth1-(-2)+(-8) x1/2 =1+2-4 =-1. Are you right?
In the end, the first two are wrong, and so are the last four. ? Correct it quickly. ?