10-4=5 10-7=3 10-5=4 10-8=2 10-9=2 10-6=8 10-5=6 10-6=4 9-8=2

Исправляем ошибки:
$$10 - 4 = 6$$
$$10 - 7 = 3$$ – верно
$$10 - 5 = 5$$
$$10 - 8 = 2$$ – верно
$$10 - 9 = 1$$
$$10 - 6 = 4$$ – верно
$$10 - 5 = 5$$
$$10 - 6 = 4$$ – верно
$$9 - 8 = 1$$
Ответ: 10-4=6; 10-5=5; 10-9=1; 9-8=1