• Comparing Family Size
• Close to 100

(pp. 2-11)

• Developing strategies for comparing two numbers
• Exploring combinations of numbers that make 100
• Using landmark numbers while making comparisons

• Cubes
• 100s charts
• 10 decks of numeral cards
• Student Sheets (SS) #1,2

• Explain to the class that they will be making many comparisons during this unit. Today you are going to compare the number of children in your family to the record number of children in a family. How should we count the number of children in our families? Whom should we count? Encourage children to talk about the questions and arrive at a consensus.
• Convey to them that we will use the data from the Guiness Book of World Records. Tell them that the Guiness definition includes all children who have the same birth mother. Ask for their estimates.
• The largest number of children in a single family was 69. This family lived in Russia about 250 years ago. It included 16 pairs of twins, 7 sets of triplets, and 4 sets of quadruplets—there were no single births.
• Ask the students: How many more children would you need in your family in order to tie the record? In other words, what is the difference between the number of children in your family and the record number of children?
• Have students work in pairs, comparing their individual family data with the record.
• Imagine that our class is a family and you are all the children in the family. What’s the difference between the number of children in this room today and the number of children in the record family? Help students to see that there are different meanings of the word difference. The difference between two quantities asks how much more there is of one thing than there is of another.
• Ask several students to share their findings with the class on how they worked out the comparisons.
• Explain how to play the game Close to 100 (see TE p. 8)
• After the game has been introduced, have the students play the game in groups of 2 or 3.

• The discussion and the game are also forms of assessment.

• Extra Practice:

• Create a class Guiness Book of World Records. Possible categories include: heaviest cat, oldest human, largest piece of fruit or vegetable, highest domino stack. The page might include the category, a drawn picture or photograph, and the appropriate measurement.