Algebra 1 · Chapter 1 · Lesson 1.5 · Printable PDF · Free

Closure Worksheet with Answer Key

8 problems on closure of number sets: naming the smallest set that holds an answer, checking closure under each operation, testing odd sets, irrational numbers, and a student's faulty reasoning. 2 pages, with a worked answer key and a one-page lesson handout. Free to download, no sign-in.

8 problems2 pagesanswer keylesson handout
Printable Closure worksheet with answer key - Algebra 1 (Page 1 PDF preview)
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What's on the worksheet

  1. Work out each answer from two natural numbers and name the smallest set that holds it.
  2. Find what is wrong with Hannah's argument about closure under subtraction.
  3. Decide if the integers greater than 10 are closed under addition, and check Ryan's subtraction claim.
  4. Test whether the natural numbers ending in 6 are closed under the operations.
  5. Simplify powers of an irrational number and say if each is rational or irrational.
  6. Give an example of each combination of irrational numbers, or explain why none exists.
  7. Show that the reciprocal of an irrational number is irrational, then use it to decide a follow-up question.
  8. Decide if the negative rational numbers are closed under each operation.

Teach it first

The free lesson teaches it with worked examples and practice problems.

Closure: the lesson ›