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Question

In one week, it rained
8
21in. If a garden needs
6
7in. of water per week, how much more water does it need?

Answer 1

I'll assume it rained (8/21) inches and the garden needs (6/7) inches, then it still needs

     (6/7) - (8/21)

      (18/21) - (8/21)         (get common denominator)

      10 /21  inch still needed   (irrigation is required)