Check out example codes for "what are the units used in css grid". It will help you in understanding the concepts better.

Code Example 1

the units used in css grid are as follows:
  1) fr: sets the column or row to a fraction of the available space.
  2) auto: sets the column or row to the width or height of its content 
            automatically.
  3) %: sets the column or row to the percent width  of its container.

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