3. 38-30+6=; 7+9+50=; 54-40-8=; 86+4-50=; 70-3-26=; 29-8+9=

Решение:

\( 38 - 30 + 6 = 8 + 6 = 14 \)

\( 7 + 9 + 50 = 16 + 50 = 66 \)

\( 54 - 40 - 8 = 14 - 8 = 6 \)

\( 86 + 4 - 50 = 90 - 50 = 40 \)

\( 70 - 3 - 26 = 67 - 26 = 41 \)

\( 29 - 8 + 9 = 21 + 9 = 30 \)

Ответ: 14, 66, 6, 40, 41, 30.