Grow: Define how the free space of flex box is distributed to its children. Specify the value
from 0 - 100. If the value is equal to 0, a flex child keeps its base size. If the value is greater
than 0, depending on the Direction set in its flex container, a flex child will be grown in
width or height to occupy the free space in flex container. The higher value the Grow
property has, the more space the object will occupy.
Shrink: When the total base size of objects is greater than the container size, objects
should be shrunk to fit the container. Specify the value from 0 - 100. If the value is equal
to 0, a flex child keeps its base size. If the value is greater than 0, depending on the
Direction set in its flex container, a flex child will be shrunk in width or height to fit the
container. The higher value the Shrink property has, the more the object will be shrunk.
To see the way they work more clearly, you can add text to objects, then change those values.