Estimate how many: tag, catch again and compare

Answer Key - Grade 7 Math Worksheet - Challenge Me

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

1. 1.

   Ari tags 40 butterflies; a later catch of 30 has 6 tagged. About how many have no tag?

   160
2. 2.

   Bo marks 25 beans in a jar; a scoop of 60 has 5 marked. About how many have no tag?

   275
3. 3.

   Esme stickers 80 snails in a garden (no snail minded); a later count of 50 snails finds 10 with stickers. About how many have no tag?

   320
4. 4.

   Jun's two later catches give estimates of 200 and 250 butterflies. Which is the best single estimate?

   • About 225
   • About 450
   • Exactly 200
5. 5.

   Kira tagged 40. Catch A: 6 of 30 tagged. Catch B: 4 of 40 tagged. Which catch gives the bigger estimate?

   • Catch B: about 400
   • Catch A: about 200
   • They give the same
6. 6.

   Milo says the meadow has 30 butterflies because 30 were caught. Agree or disagree?

   • Agree: 30 is a round number
   • Agree: the catch is everyone
   • Disagree: 30 is only a sample
7. 7.

   Noah says the jar holds 48 beans because the scoop held 48. Agree or disagree?

   • Agree: the scoop counts the whole jar
   • Agree: 48 is close to 60
   • Disagree: scale up with the ratio
8. 8.

   Pia says the tag-and-catch method gives the exact number of turtles. Agree or disagree?

   • Disagree: it is an estimate
   • Agree: proportions are exact
   • Agree: turtles stay put
9. 9.

   Some of Ren's shell stickers fall off before the second count. What happens to the estimate?

   • It stays exact
   • It comes out too small
   • It comes out too big
10. 10.

    Many new snails hatch between Zee's two counts. Why is that a problem?

    • New ones change the mix
    • Snails lose their stickers
    • The ratio gets exact