Math in Action 2014-2015 Welcome to the first math challenge of 2014-2015. We invite you to participate in all 15 math challenges planned for the school year. A schedule of the challenges and due dates are listed online at the Math in Action website (www.mathinaction.org). Students in Kindergarten through 5th grade are invited to take part in solving these fun math problems. Parents and siblings are encouraged to discuss these math problems with students. Students who submit qualified answers to at least 12 math challenges will be honored at the award assembly in June 2015. Notes to Parents There are seven strategies that will be covered in 2014-2015 math challenges: work backward, draw a picture/diagram/model, look for patterns, make an organized list or a table, act out the problem, guess and check, and use logical reasoning. There is an explanation and examples for each strategy on the website. Feel free to check them out. If you are new to our format of math challenge, we often group problems so students focus on one or two strategies. For example, math problems in our first challenge can be solved using logical reasoning and/or drawing a picture/diagram/model. However, since students learn in different ways, some students may wish to use a strategy other than the one(s) suggested in the math challenge. If students come up with more than one strategy, encourage them to use the best method for them. We want to equip them with these strategies but we also want them to be flexible in applying them. As they become more skilled, they may combine two or more strategies to effectively solve problems. If students get stuck on a problem, try not to offer the solution right away. Start a discussion about strategies and reread the problem together. If students enjoy math, try to challenge them to solve more problems than required. ***** Our first Math Challenge is about digits and numbers. Digits and numbers are like letters and words. In the vocabulary world we use letters to write words. In the number world we use digits to write numbers. Numbers are used to express amount, total or measurement. We also use them for labels (telephone numbers), for ordering (serial numbers), and for codes. The following are definitions of words that may help you solve this first Math Challenge. Vocabulary: Consecutive Numbers - numbers which follow each other in order, without gaps, from smallest to largest. Even number - numbers ending with 0, 2, 4, 6 or 8. Also, any integer that can be divided exactly by 2. Odd number - numbers ending with 1, 3, 5, 7 or 9. Also, any integer that cannot be divided exactly by 2. Sum - the result of adding two or more numbers. Product - the result of multiplying two or more numbers. Prime Numbers – numbers only evenly divisible by 1 and itself. 1 Math in Action 2014-2015 First Name: ____________________ Last Name: ____________________ Grade: _______ Teacher: ________________ Your solutions are due on Thursday, October 9 (no later than 3 p.m.). Submit your solutions to your teacher or to your school office by the due date. Kinder & First Grade: Solve at least 4 problems correctly. Second & Third Grade: Solve at least 9 problems correctly. Fourth & Fifth Grade: Solve at least 14 problems correctly. Digits and Secret Numbers 1. My secret number is a two-digit number. The first digit is the number of your eyes, and the second digit is the number of fingers on your right hand. Answer: 2. How many even digits are in the number 13,056? _____________ Answer: 3. What is the sum of odd digits in the number 55,012? _____________ Answer: 4. My secret number is the sum of the number of fingers on my left hand plus the number of all of my toes. 5. Sophia’s secret number is a three-digit number. The digits are in counting order. If you add the digits, the sum is 12. What is Sophia’s secret number? _____________ Answer: _____________ Answer: _____________ 6. The sum of two consecutive numbers is 13, what are the numbers? 7. Guess Rachel’s secret number. The number is greater than the number of days in November but it is less than the number of inches in six feet. It is an even number, and if you count by 10s, you say the number. The sum of its digits is equal to the number of days in a week. 8. Using each of the digits 1, 2, 3, 4, 5, 6, 7, 8, and 9 only once, fill in the rectangles to make three mathematical sentences. + = - = × = Answer: Answer: _____________ Answer: 2 Math in Action 2014-2015 9. Guess Anita’s secret number. The number is greater than the number of pennies in a quarter. It’s less than the number of pennies in 5 dimes. It is an odd number. If you count by 5s, you say the number. The sum of the digits is 8. What is Anita’s secret number? 10. Each letter below represents a different digit. Can you decipher the following so that it makes a correct multiplication problem? Answer: _____________ Answer: ___________ BA x 7 = HAA 11. Can you arrange these five digits 1, 2, 3, 4, 5, so that the first two digits multiplied by the middle digit will produce the last two digits? Answer: 12. 13. × = You take a two-digit number, reverse its digits to make a second two-digit number, and add these two numbers together. If the answer is 121, what are all the possible two-digit numbers? Maria’s secret number is a prime number that is larger than 20 but less than 50. The sum of its digits is 10. What is Maria’s secret number? Answer: ___________ Answer: ___________ 14. 15. 16. Find Aditi’s number. The hundred’s digit is an even number between 5 and 8. The ten’s digit is 3 less than the hundred’s digit. The one’s digit is the hundred’s digit plus the ten’s digits. Answer: In the multiplication problems below, A, B, C, and D represent different digits. ABC is a three-digit number, and * means multiplication. What three-digit number does ABC represent? What number does D represent? ABC * D 1673 Answer: The digit 3 is written at the right of a certain two-digit number thus forming a three-digit number. The new number is 372 more than the original two digit-number. What was the original two-digit number? Answer: ___________ ___________ ___________ Math Challenge 2 will be available online October 17, 2014 at www.mathinaction.org. Math Kangaroo and Fall NLMC registration is now open. Links are available at www.mathinaction.org. 3
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