Jhonatan ate 9/12 of a hotdog, he saved 4/9 of it for his little sister. How much of the hot dog did his little sister eat?

(3/12) * (4/9) = 12/108 = 1/9

To find out how much of the hotdog Jhonatan's little sister ate, we need to subtract the portion Jhonatan saved for her from the portion Jhonatan ate.

Jhonatan ate 9/12 of the hotdog, which can be simplified as 3/4.
So, Jhonatan saved 4/9 of 3/4.

To calculate this, we multiply the fractions:
4/9 * 3/4 = (4*3) / (9*4) = 12/36

Therefore, Jhonatan saved 12/36 of the hotdog for his little sister.

To find out how much his little sister ate, we subtract the portion he saved for her from the portion Jhonatan ate:
3/4 - 12/36 = 9/12 - 12/36

We need to find a common denominator for 12 and 36 which is 36. So, we convert 9/12 to have a denominator of 36:
(9/12) * (3/3) = 27/36

Now we can subtract:
27/36 - 12/36 = (27 - 12) / 36 = 15/36

Therefore, Jhonatan's little sister ate 15/36 of the hotdog.