You probably are smart enough not to need many answers. Many of the activities are self-checking and you can figure out the reason if the outcome seems wrong. Finding your own mistakes gives you a feeling of success and is a lot more challenging than looking in the back of the book for the answer.
Here are some answers to help you check your work.
CHAPTER 1
Shape of the Board (page 26)
Triangle: 16; pentagon: 28; hexagon: 34
CHAPTER 3
The Calendar of the Maya (page 49)
1. a. 3,738 days
b. 6,009 days
c. 5,383 days
3. 18,132 days, or more than 49 years, including 12 leap years (13, if the first year is a leap year). Therefore 18,132 days = 49 years and 235 days.
Wampum, Cocoa Beans, and Pieces of Eight (page 49)
1. a. 36 strings
b. 316 strings
5. One quarter = 25 cents, or one quarter of a dollar; 12 bits
Save Those Cans (page 58)
1. 260 cans
2. 975 hours, or 195 days if TV sets run 5 hours per day
3. About three billion gallons
Saving the Lives of Children (page 60)
1. 2,000 ORT packets; 2,500 supplies of vitamin A; 16 sets of warm clothes; seeds for over 10,000 pounds of food
CHAPTER 4
Magic Squares from China and the Muslim World (page 70)
Save the Water (page 78)
1. 40 cups = 2½ gallons
2. 39 cups
3. 78 cups per day; 546 cups = 34
gallons per week; 28,470 cups = 1,779 gallons per year
CHAPTER 6
Möbius Strip Surprises (page 96)
When you cut the strip through the middle, the result is a loop twice as long but half as wide as the original. When you cut one-third of the way from the edge, the outcome is two connected loops. One is twice the length of the original strip and the other is the same length as the original. Both are one-third the width of the original strip.
Sand Drawings-Part I:
Animal Pictures, Things to Think About (page 98)
1. Two lines of symmetry; two turn positions
2. No line of symmetry; two positions in which the figure looks the same as it is turned
CHAPTER 7
Native American Beadwork-Part I (page 108)
3. 100 beads
5. 400 beads
6. Four
Native American Beadwork-Part II (page 110)
3¼square cm; 128 beads