Previous Next HighlighterHighlighter NotesNotes
Yellow
Green
Blue
Red
Magenta
Remove

LESSON 6 Using Estimation

Mystery Jars

Linda took this photograph of a flock of birds.

Then she copied part of her picture using a computer and made the smaller picture at the right. Linda says that the smaller picture has about 25 birds.

  1. Use the number of birds in the small picture as a reference number to help you estimate the number of birds in the larger picture.
  2. Explain how you reached your estimate.

One way to make good estimates is to compare the quantity you want to estimate with a known number of objects.

Tanya made a mystery jar filled with marbles. Then she put 50 other marbles in a plastic bag. Tanya showed the jar and the bag of marbles to the other students. She asked them to guess how many marbles were in her mystery jar.

  1. How is Tanya's mystery jar problem like Linda's picture problem?

Jacob said the small bag of marbles helped him to guess how many were in the large jar. He said, “It looks like I could fit about 4 of these bags of marbles into the big jar. So I'm going to say my estimate is 200 marbles in the big jar.”

  1. How did Jacob decide on his estimate of 200 marbles?