[9 1/5 -3,68):2 1/2]*[ 1:(2,1- 2,09)] = 3220
3 4 5 2 1
1. 2.1 - 2.09 = 0.01
2 1 : 0.01 = 1 : 1/100 = 1 * 100 = 100
3. 9 1/5 - 3.68 = (9*5+1)/5 + 3 68/100 = 46/5 + 3 17/25 = 46*5/25 + (3*25+17)/25 = 230/25 + 92/25 = 322/25
4. 322/25 : 2 1/2 = 322/25 : 5/2 = 322/25 * 5/2 = 161/5
5. 161/5 * 100 = 161 * 20 = 3220