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.

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

   • Catch A: about 200
   • They give the same
   • Catch B: about 400
5. 5.

   Why might Luz do the second catch several times?

   • To make the numbers smaller
   • To tag each one of the butterflies
   • Averaging gives a steadier estimate
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?

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

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

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

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

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

    Tala's tagged butterflies stay near one bush and don't mix. What could go wrong?

    • The tags stop working
    • Nothing changes
    • The catch's tagged share is off