5. 7,21,2/6. 3제곱x7 , 2x3제곱x5 , 2x3 / 7. 18,12,9/ 8. 3,4,6,8,12,24/ 3,4,6,9,12,18,36 / 12명 // 9. 20cm , 20개/ 10. 2,60/ 4,110/ 60,110.최대공약수.10/ 8p: 455444,12,24 / 9p~11p : 1.4,8,12,16,20,24,… // 6,12,18,24... // 12,24,...// 12// 12,24,12, 배수 // 2. 18, 36// 18 // 18, 36// 3. 24,48,72// 60,120,180 // 4. 2,12,9,2