(a) Rounding off 11963 to nearest tens = 11960

Rounding of 9369 to nearest tens = 9370

11960 - 9370 = 2590

(b) Rounding off 76877 to nearest tens = 76880

Rounding of 7783 to nearest tens = 7780

76880 - 7780 = 69100

(c) Rounding off 10732 to nearest tens = 10730

Rounding of 4354 to nearest tens = 4350

10730 - 4350 = 6380

(d) Rounding off 78203 to nearest tens = 78200

Rounding of 16470 to nearest tens = 16410

78200 - 16410 = 61790