All skills can be usefully divided into 3 categories: concept skills, calculation skills, and tool skills.
Concept Skill vs Tool Skill
Consider understanding how a car works (engine consumes fuel to spin wheels while driver steers) vs the ability to actually drive a car (use key, open door, sit down, start ignition, wear seatbelt, shift gear to drive/reverse, etc).
Consider understanding the difference between symmetric and asymmetric encryption (ex. passwords, public-private keypair) vs the ability to actually send a specific file to a specific server using SFTP technology (install SFTP client, open command line or GUI, type the right user/hostname/port combination, attempt to connect with password or configured private key, etc).
Calculation Skill vs Tool Skill
Consider determining the size of a product to fit a sheet of paper with an effective manufacturing tolerance (area of 220mm by 385mm) vs the ability to actually create its 3D model in a design program (ex. using MCAD software like Autocad or Solidworks to generate the design file with the desired dimensions and features).