2 5 6 7 11 8 10 ( ) 4 18 6 10 12 9 20 2 6 7 11 4 4 4( ) 1 4 3 5 5 6 4 2 6 7 11 4 4 4( ) 1 4 3 5 5 6 4 7 4 6 8 4 8 6 5( ) Problem solving method

2 5 6 7 11 8 10 ( ) 4 18 6 10 12 9 20 2 6 7 11 4 4 4( ) 1 4 3 5 5 6 4 2 6 7 11 4 4 4( ) 1 4 3 5 5 6 4 7 4 6 8 4 8 6 5( ) Problem solving method

Gaga 2567 11810 (9) 4186 10129 20 group 1: 5 + 6 = 11-11 = 0.7-2 = 5 group 2: 10 + 9 = 19-18 = 1.8-4 = 4 group 3: 12 + 10 = 22-20 = 2.9-6 = 37 468 4865 (2) group 1: 7-4 = 3.3 + 3 = 6 group 2: 8-4 = 4.4 + 4 = 8 group 3