Answer:
2/5
Explanation:
Since it's from a big square to a smaller square, the smaller number will be at the top. Also, use the same side to find the scale factor, but since this is a square and all sides of a square are equal, it doesn't matter but in other shapes it does so practice i guess:
Left side of big square: 5
Left side of small square: 2
So scale is 2/5
To confirm:
5 · 2/5 = 10/5 = 2, we're right