Directions –

(i) Closest base = 10, so deviations are -1 and 1.

(ii) Multiplication of deviations = -1 × 1 = -1.

(iii) On the left hand side, write 9 + 1 = 10 or 11 – 1 = 10.

(iv) Negative number can not be put on right side. So borrow one carry from left side and make it positive.

(v) On the left and side, write 10 – 1 = 9.

(vi) Required solution is 99.