Решение:
- \( 18:(12:2) = 18:6 = 3 \)
- \( 21:(14:2) = 21:7 = 3 \)
- \( 15:(10:2) = 15:5 = 3 \)
- \( 8:(2*2) = 8:4 = 2 \)
- \( 16:(10:5) = 16:2 = 8 \)
- \( 9*(21:7) = 9*3 = 27 \)
- \( 8*(15:5) = 8*3 = 24 \)
- \( 7*(9:3) = 7*3 = 21 \)
- \( 4*(18:9) = 4*2 = 8 \)
- \( 3*(12:2) = 3*6 = 18 \)
Ответ: 1) 3; 2) 3; 3) 3; 4) 2; 5) 8; 6) 27; 7) 24; 8) 21; 9) 8; 10) 18.