1. 13 - 4, 13 - 7, 13 - 5, 13 - 8, 13 - 9, 13 - 6, 12 - 5, 11 - 2 + 7, 12 - 6, 5 + 6 - 8, 12 - 8, 8 + 9 - 1

Вычисления:

\( 13 - 4 = 9 \)

\( 13 - 7 = 6 \)

\( 13 - 5 = 8 \)

\( 13 - 8 = 5 \)

\( 13 - 9 = 4 \)

\( 13 - 6 = 7 \)

\( 12 - 5 = 7 \)

\( 11 - 2 + 7 = 9 + 7 = 16 \)

\( 12 - 6 = 6 \)

\( 5 + 6 - 8 = 11 - 8 = 3 \)

\( 12 - 8 = 4 \)

\( 8 + 9 - 1 = 17 - 1 = 16 \)