Math Crossword

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Across
  1. 3. / putting two things together
  2. 5. / a portion of something
  3. 7. / the study of shapes
Down
  1. 1. / taking something from something else
  2. 2. / the outside lining of something
  3. 4. / splitting something into equal or non-equal groups
  4. 6. / the inside space of something