## Teacher Guide: Lesson 6.4

The Weekly Reader Connections feature on Kids' Place Houghton Mifflin Math provides your students with additional information about the topics that appear in the Curriculum Connection feature in their student books.

The article “The Maya: Where Did They Go?” discusses recently revealed hieroglyphs, whose interpretation suggests possible reasons for the disappearance of the Mayan civilization. Have students read and discuss the article.

Have students do the Word Wise activity, which focuses on the prefixes “astro-” and “trans-.” Record the words that students suggest on the board and encourage a discussion of the meaning of each.

Astro-
Trans-
Possible responses:

• astrodome
• astronaut
• astronomer
• astronomical
• transfer
• transform
• transmit
• transplant

Students should develop the understanding that words with the prefix astro- have something to do with stars and words with the prefix trans- have something to do with moving across or through.

The Data Hunt provides students with the dual challenge of first interpreting the way in which Maya wrote their numbers using their base-20 system and then applying that understanding to the addition of two “Mayan” numbers.

Students should discuss their responses to questions 1-4 with their groups before talking about them with the whole class. You may wish to enlarge the page to display it, or copy the columns of dots and bars onto the board, for the class discussion.

Be sure that students understand how all the elements in columns A and B were combined to create column C. You may need to explain that four bars at the bottom of column C, which represent 20, were regrouped as one dot at the top of column D (1 x 20 = 20). Finally, students should understand that column D represents (4 x 20) + 9 = 89, which is the sum of 34 and 55.