101-{5×[4×(28+4:2):10]:6+90}=x-1
101-{5×[4×(28+2):10]:6+90} = x - 1
101 - [5×(4×30:10) : 6 + 90] = x - 1
101 - [5×(4×3):6 + 90] = x - 1
101 - (5 × 12 : 6 + 90) = x - 1
101 - (5 × 2 + 90) = x - 1
101 - (10 + 90) = x - 1
101 - 100 = x - 1
1 = x - 1
x = 1 + 1
x = 2