This is a demo for contest for 6th grade but the questions are not necessarily suitable for you. 

[1] A shirt was charged $1.96 with a 4% sales tax rate included. What was the cost of the shirt(in dollars)before the tax was included?

[2] Niconia has 3 shirts, 5 pants, and 3 shoes. How many different ways can she dress up?

[3] John has 4 choices of roads from home to school. There are 5 choices of roads from school to library. How many choices of roads does John have if he gets to school from home, then goes to the library from school?

[4] Eric rode his bike to a baseball practice at 15 mph. On his way home, he only pedaled at 10 mph. What was his average speed (in mph) for the entire trip?

[5] Laura went shopping. She spent one-third of her money in the 1st store. She went to a second store where she spent one-fourth of what remained, and then had $102 left. How much money (in dollars) did she have before she went to the 1st store?

[6] There are 80 balls of 8 different colors in a bag. There are an equal number of balls for each color. At least how many balls need to be taken out from the bag so that there are 4 balls which are of the same color?

[7] If 12+22+32+ ...+272+282+292 = 8555, what is the value of 22+42+62+ ...+542+562+582 =?

[8] There are one $5 bill, four $2 bills, and eight $1 bills. If Ben needs $9, how many ways could he make up the money from those bills?

[9] Express the following sum as a simple fraction in lowest terms:

[10] A series of numbers '345678345678345678...' has a certain pattern. What is the sum of the first 84 digits in the number starting from the left side?