Can anyone tell me how to get 7+1=9. It is a tricky question of maths?

Yes it is a tricky question... and it's incomplete!

The only way to make it work is to use vectors... 7 units in one direction plus 1 unit in another direction = 9 units total... but there is no solution for 7 + 1 = 9. the maximum solution is 8 and the minimum is 6.

If we're going to ignore the rules of math for the sake of solving the problem, then either the 1 or the 7 can really be anything you want. For Example:

7 units north + 1 double unit north = 9 units north total.

regards!

(and if a teacher is asking you this, good luck in that class... any prof. who would ask something like this on homework revels in his or her own superiority and would not be an effective teacher except to a student who revels in being superior)

If you had rounding errors, it could be done. For instance:

7.4 + 1.4 = 8.8

This statement is true, and if you rounded each to the nearest whole number, you would see:

7 + 1 = 9

its not a tricky question its a funny question

7single + 1double=9single