MathCounts

If each of the digits 2, 3, 4 6, 7 and 8 is used exactly once to construct two three-digit  numbers (m) and (n) , what is the smallest positive value of the difference of m - n? 

• 39
• 52
• 41
• 63

The sum of Madison's age and 3 times Harper's age is 47 years.  In two years, Madison will be twice as old as Harper.  How old is Harper?

• 12
  12
• 16
• 9
• 14

For how many positive integers containing no digit of zero is the sum of the digits equal to 5?

• 12
• 14
• 16
• 18

The four positive integers P, Q, P + Q, and P-Q are all prime and their sum is S.  What is the value of S?

• 13
• 17
• 25
• 23

How many factors of 2940 are perfect squares?

• 4
• 6
• 8
• 16

What is the largest prime factor of this year?

• 3
• 13
• 31
• 16

A two-digit number times a one-digit number will yield a three digit number. If each of the digits 1-6 are the solution, what is the problem?  Why is this?

• 23 * 4 = 145
• 54 * 3 - 162
• 12 *6 = 345
• 62 * 3 = 415

Mollie has fewer than 100 pennies.  If she puts the pennies in stacks of five, there are three pennies left over.  If she puts them in stacks of seven, there is one penny left over.  If she puts them in stacks of three, there are no pennies left over.  What is the total number of pennies Mollie has?

• 93
• 84
• 69
• 78

How many positive integer factors does 96 have?

• 21
• 12
• 13
• 15

If (n) is an even integer such that 0 < n <10, what is the sum of all possible unit fractions of the form 1/n?  Express your answer as a common fraction.

• 25/24
• 7/8
• 12/11
• 18/16