Turn the 6 upside down.
It then becomes a 9.
9+(-3)=6 6-(-3)=9
Add something to NINE to make it SIX IX is a Roman Numeral for 9 Add/ Prefix S to it to make it SIX
9x9+9+9+9/9
Add something to NINE to make it SIX IX is a Roman Numeral for 9 Add/ Prefix S to it to make it SIX
Add -3 to 9 because 9+(-3) = 6 Alternatively add s to the Roman numeral of ix which is 9 which then becomes six.
( 9+9+9) / (9+9+9)= 1 or 999 /999 = 1
Add something to NINE to make it SIX IX is a Roman Numeral for 9 Add/ Prefix S to it to make it SIX
720 of them.
Roman numeral IX is 9, so six would be VI, IIIIX or IVX.
Six
Oh, what a happy little challenge! To make 9 with six sixes, you can add 6/6 + 6/6 + 6/6 = 9. Isn't that just delightful? Remember, there are many ways to approach a problem, and it's all about enjoying the process of creating something wonderful.
Are you sure you mean "letter" and not "number" ? If number, then it is -3. In terms of letter, well, it is a puzzle. 9 can be written as IX in Roman numerals. So, if you add S to it, it becomes SIX.