Условие:

90 − (486);
60 − (522);
64 + (18 + 2);
70 − (9 + 9);
8 + 97;
6 + 78.

90 − (486) = 9042 = 48;
60 − (522) = 6050 = 10;
64 + (18 + 2) = 64 + 20 = 84;
70 − (9 + 9) = 7018 = 52;
8 + 97 = 177 = 10;
6 + 78 = 138 = 5.