What is the scale factor

2/5

Step-by-step 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