Question

appropriate tools
using tools that fit properly is of major importance. this goes for both imperial (standard) and metric nuts and bolts. a large force can be transferred, if the tool fits snugly over the nut or bolt. an undersized tool will not fit over the nut or bolt and an oversized tool will have too much play and will slip off; resulting in a damaged nut or bolt.
metric
metric wrenches usually have the size in millimeters stamped on the handle. widely used sizes for metric tools are: 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 21 mm, 22 mm and 24 mm.
imperial
imperial (standard) wrenches have the size in fractional inches stamped on the handle. widely used sizes for imperial tools are: 1/4\, 5/16\, 3/8\, 7/16\, 1/2\, 9/16\, 5/8\, 11/16\, 3/4\, 13/16\, 7/8\, 15/16\, 1\, 1 1/16\, 1 1/8\ and 1 1/4\.
2
which size designations can you find on a metric wrench?
13 mm
1/4\
10 mm
3/8\

Explanation:

The text states that metric wrenches have sizes in millimeters stamped on the handle. So, sizes in inches are for imperial wrenches, not metric ones.

Answer:

13 mm, 10 mm