FACTORS
COUNTING
DIGITS
RANDOM
200

What is the 3rd largest factor of 627?

57

200

On Planet Cat, the only letters are C, A, and T.  A word is any sequence of no more than four letters, and repeats are allowed.  How many words are there on Planet Cat?

120

200

What is the units digit of  32025?

3

200

Thomas was asked how old he is.  He said, "In two years I will be twice as old as I was five years ago."  How old is Thomas?

12

300

When 391 is divided by a positive two-digit number N,  the remainder is 6.  Find all the possible values of N.

11, 35, 55, 7

300

How many distinct ways are there to arrange 5 identical white blocks and 3 identical red blocks in a straight line?

56

300

In the equation AT + AT + AT = BAT, the same letter always stands for the same digit, and different letters stand for different digits.  What is the 3-digit number BAT?

150

300

A graph has 11 vertices.  Each vertex is connected to exactly k other vertices.  How many different values of k are possible, if we know k is greater than 0?

5

400

How many factors of 100,000,000 are not factors of 100,000?

45

400

My local pizza restaurant offers 10 different pizza toppings.  How many different types of pizza can I order that have at least 2 toppings?  (Remember order doesn’t matter in pizza toppings).

1013

400

How many 9-digit numbers are there such that going from left to right the digits of the number get smaller?

10

400

There are 26 kids at a party and together they eat a total of 100 slices of pizza.  Alice ate 1 slice, Ben ate 2 slices, Christina ate 3 slices, and Zach ate more slices than anyone else.  What is the smallest number of slices that Zach could have possibly eaten?

6

500

Determine how many factors of N are perfect squares where N =  3! * 5! * 7!

30

500

How many 10-digit numbers have the sum of their digits equal to 3?

55

500

Sarah writes out all numbers between 1 and 999. How many times did she write the digit 5?

300

500

How many two-digit numbers give a perfect square when added to their “mirror” (the two-digit number written with its digits in reverse order)?    For example, if you add 93 and 39 you get 132, which is not a perfect square.

8

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