Estimate how many: tag, catch again and compare

Answer Key - Grade 7 Math Worksheet

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

1. 1.

   Ari tags 50 ladybugs in a garden. Later, 40 are caught and 8 have tags. About how many are there in all?

   250
2. 2.

   Bo marks 60 beans and mixes them into a big jar. A scoop of 48 beans has 12 marked ones. About how many are there in all?

   240
3. 3.

   Esme puts stickers on 30 turtles' shells. Later, 50 turtles are spotted and 5 have stickers (they look very proud). About how many are there in all?

   300
4. 4.

   Jun tagged 50 ladybugs; a later catch of 40 had 8 tagged. Which proportion finds the total N?

   • 8/50 = N/40
   • 8/40 = 50/N
   • 40/8 = 50/N
5. 5.

   In Luz's ratio table, which row goes with the whole garden?

   • 8 tagged, 40 in all
   • 50 tagged, N in all
   • 40 tagged, 50 in all
6. 6.

   Milo's second catch has fewer tagged butterflies than expected. What does that suggest about the meadow?

   • More butterflies than thought
   • Fewer butterflies than thought
   • No butterflies of any kind
7. 7.

   Noah tagged 30 fish in a class aquarium study, and half the next catch is tagged. About how many fish are there?

   • About 60
   • About 15
   • About 30
8. 8.

   In Pia's second catch, every turtle has a sticker. What does that suggest?

   • The pond holds many more
   • Stickers multiply
   • Nearly all were tagged already
9. 9.

   Tala marks 30 marbles in a bag, mixes, and draws 20: 4 are marked. About how many marbles are in the bag?

   • About 54
   • About 24
   • About 150
10. 10.

    Why can Zee's bean-jar method also estimate fish in a lake?

    • Both are counted one by one
    • Beans and fish weigh the same
    • Both use a marked share