WASHINGTON STATE MATHEMATICS COUNCIL 2000 MIDDLE SCHOOL MATH OLYMPIAD Session II ANSWERS: NOTE: Take off half-credit if units were asked for in the question but not provided by the team.

5/6

5 FIFTH GRADE

Number Sense

1. 20

2. 11

3. 105

4. 1

5. 5/12

Measurement

1. 140

2. 25

3. 20% (2 points for 19.722%)

4. 57,600

5. 4 inches

Geometric Sense

1. 91

2. 36

3. 8

4. Any answer between 77,256 and 77,400 sq. ft. inclusive

5. Any answer between 25.12 and 25.133 sq. cm. inclusive

Probability & Statistics

1. 1/2 or 5/10

2. 165 (Give 2 pts. for mean=84, mode=81)

3. 1/18 or 2/36

4. 97

5. 360

Algebraic Sense

1. 4

2. 10

3. 6*

W must be 5 or greater to cause the O in the hundreds column of the sum to be 7 (odd). 5 would not work, because it would cause the letter U and the letter F both to be worth 1. 8 would not work because T must be 8 to yield a sum of 17 with the carried 1 hundred. W could not be 9 because it would cause U to be 9. The numbers are as follows: 867 + 876 = 1724

4. 108 (Give 2 pts. For 27, 36, 45)

5. 152

6 SIXTH GRADE

Number Sense

1. 11

2. 6

3. 5/12

4. 9%

5. 24

Measurement

1. 96

2. 25

3. 57,600

4. Saturday

5. 3.75 inches or 3 3/4 inches

Geometric Sense

1. 8

2. 400% or 4 times (Give 2 points for 4.)

3. Any answer between 77,256 and 77,400 sq. ft. inclusive

4. Any answer between 25.12 and 25.133 sq. cm. inclusive

5. 15 in.

Probability & Statistics

1. 246 (give 2 pts. for mean 84, mode 81, median 81)

2. 97

3. 360 (6x5x4x3x2)/2

4.   180 (5x4)/2 x (3x2)/2 x (4x3)/2

5.   1/29

Algebraic Sense

1. 4

2. 10

3. 36

4. $75

5. 12