Hands-on math!

Washington State Math Olympiad
Hints and Solutions
2007 Grade 8 Number Sense

Problem
1) The length of a picture is enlarged by 50% and the width is enlarged by 25% producing an odd looking picture. By what percent is the area enlarged? Express your answer to the nearest tenth of a percent.

2) The number 6  __ ,  __  __  6 is a perfect square that is a palindrome, so it reads the same forwards as backwards. What are the missing digits in order?

3) Jona takes 1/3 of his Halloween candy to school to sell. It went so well that the next day he takes 2/5 of the Halloween candy left over to school to sell. When he gets home he gives 6 pieces to his baby sister because he's in such a good mood. What's the smallest amount of candy he could have had to start with if he still has candy left over?

Problem
4) How many integers n satisfy (n + 4)(n - 6) ≤ 0 ?


5) The sum of the first 100 positive odd numbers is 1002. What is the sum of the first 100 positive even numbers?