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.

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

   • About 225
   • Exactly 200
   • About 450
4. 4.

   Why might Luz do the second catch several times?

   • To make the numbers smaller
   • Averaging gives a steadier estimate
   • To tag each one of the butterflies
5. 5.

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

   • Disagree: 30 is only a sample
   • Agree: 30 is a round number
   • Agree: the catch is everyone
6. 6.

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

   • Disagree: scale up with the ratio
   • Agree: 48 is close to 60
   • Agree: the scoop counts the whole jar
7. 7.

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

   • Disagree: it is an estimate
   • Agree: turtles stay put
   • Agree: proportions are exact
8. 8.

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

   • It stays exact
   • It comes out too big
   • It comes out too small
9. 9.

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

   • Nothing changes
   • The tags stop working
   • The catch's tagged share is off
10. 10.

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

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