(1 целая 3/4+0,91)÷1,4+(1 целая 1/5-1,911)×1 целая 21/79 =?

1) 1 3/4 + 0,91 = 7/4 + 91/100 = 175/100 + 91/100 = 266/100
2) 266/100 : 1,4 = 266/100 : 14/10 = 266/100 * 10/14 = 19/10
3) 1 1/5 - 1,911 = 6/5 - 1911/1000 = 1200/1000 - 1911/1000 = -711/1000
4) -711/1000 * 1 21/79 = -711/1000 * 100/79 = -9/10
5) 19/10 + (-9/10) = 10/10 = 1