Estimate how many: tag, catch again and compare

Answer Key - Grade 7 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Ari nets 40 butterflies in a meadow, and 8 of them have the dot Ari painted on last week. What fraction of this catch is tagged?

   1/5
2. 2.

   Bo scoops 48 beans from a jar, and 12 of them are the marked beans Bo mixed in. What fraction of this catch is tagged?

   1/4

3. Read this first

   Ratio table for tag and catch again (butterflies in a meadow) (example data)

   row	tagged	total
   second catch	6	30
   whole meadow	40	?

4. 3.

   Using the table, what share of the second catch is tagged, Jun?

   • 6 in 40
   • 1 in 5
   • 1 in 6
5. 4.

   Using the table, about how many butterflies live in the meadow, Kira?

   • About 200
   • About 40
   • About 36
6. 5.

   Using the table, what does the 40 stand for, Luz?

   • Butterflies tagged at first
   • The butterflies in the meadow in total
   • Butterflies in the second catch
7. 6.

   Why can Milo use one catch to estimate the whole meadow?

   • Tagged ones fly slower
   • Each butterfly is caught on a single day
   • Its tagged share matches the meadow's
8. 7.

   Why does Noah wait a few days before the second catch?

   • So more are born first
   • So the tagged ones mix back in
   • So the painted tags can wear off
9. 8.

   What happens to the butterflies after Pia counts them?

   • They are let go unharmed
   • They are kept in jars at school
   • They are moved away
10. 9.

    Which second catch gives Tala a more reliable estimate?

    • A random catch of 60
    • The first 6 seen by the gate
    • A random catch of 6
11. 10.

    Why does Zee shake the bean jar before scooping again?

    • To count them faster
    • To mix the marked beans in
    • To break the beans into halves