Properties of equality and 1 more thing.

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Across
  1. 6. a=b, then a-c=b-c
  2. 8. real #a, a=a
  3. 9. a=b, then a/c=b/c
  4. 10. p-> q, q-> r, three dots p -> r
Down
  1. 1. a(b+c) = ab+ac
  2. 2. a=b, the b=a
  3. 3. a=b, then a+c=b+c
  4. 4. a=b, a replaced by b.
  5. 5. a=b, then a(c)=b(c)
  6. 7. a=b and b=c, then a=c