Learn Basic JavaScript by Building a Role Playing Game - Step 72

this challenge is a little bit unclear for me can anyone explains it to me

Challenge Information:

Learn Basic JavaScript by Building a Role Playing Game - Step 72

You can look at the example as shown in the step. And reread the step, it’s too easy.

You can see the example it’s “num = num - 5;” so what is want is you do the same thing but the variable change to gold and minus 10