Which pair of measurements is not equivalent?

4 lb., 64 oz.
3 tons, 6,000 lb.
108 oz., 8 lb.
10,000 lb., 5 tons

If you would like to know which pair of measurements is not equivalent, you can calculate this using the following steps:

1 lb = 16 oz
1 ton = 2,000 lb

4 lb = 4 * 16 oz = 64 oz
3 tons = 3 * 2,000 lb = 6,000 lb
8 lb = 8 * 16 oz = 128 oz
5 tons = 5 * 2,000 lb = 10,000 lb

Not equivalent: 108 oz., 8 lb.