(0,8 - 2/3) * 2 1/2 + 2

0,8 = 8/10 = 4/5 - сократили на 2
2 целых 1/2 =  (2*2+1)/2 = 5/2
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(0,8 - 2/3) * 2 1/2 + 2 = 2 1/3
1) 0,8 - 2/3 = 4/5 - 2/3 = 12/15 - 10/15 = 2/15
2) 2/15 * 2 1/2 = 2/15 * 5/2 = 5/15 = 1/3 
3) 1/3 + 2 = 2 целых 1/3