Kuba four-digit number

Kuba wrote down a four-digit number, two evens, and two odds. If he crossed out both even digits in that number, he would get a number four times smaller than if he crossed out both odd digits in the same number. What is the most significant number with these characteristics that Kuba could write down?

Final Answer:

x =  6817

Step-by-step explanation:

$$\begin{gathered} 48=4\cdot 12 \\ 52=4\cdot 13 \\ 56=4\cdot 14 \\ 60=4\cdot 15 \\ 68=4\cdot 17 \\ 72=4\cdot 18 \\ 76=4\cdot 19 \\ 84=4\cdot 21 \\ 96=4\cdot 24 \\ x=6817 \end{gathered}$$

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