math holiday homework

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Across
  1. 3. _____ is identity for addition of whole numbers
  2. 7. Identify this property (5+4)+9 = 5+(4+9)
  3. 8. Identify this property 8(9+4)
  4. 9. division by _____ is not defined
  5. 11. 20-(10-3+2)
Down
  1. 1. The numbers 0,1,2,3 form the collection of
  2. 2. Identify this property 2+4=4+2
  3. 4. ____ is distributive over addition for whole numbers
  4. 5. natural numbers start from
  5. 6. the numbers 1,2,3 form the collection of
  6. 10. whole numbers start from