What least number must be subtracted from 1294 so that the remainder when divided by 9, 11, 13 will leave in each case the same remainder 6?

L. C .M of 9, 11, 13 is 1287
On dividing 1294 by 1287, the remainder is 7 .
∴ 1 must be subtracted from 1294, so that 1293 when divided by 9, 11, 13 leaves in each case the same remainder 6 .