**Problem:**

Number Concepts-Integers (**InterMath**)
**Jeff had fewer than 100 blocks. When he made five
equal rows, he had only one left over; with four equal rows, he
had one left over; and with nine equal rows, he had none left
over. How many blocks did Jeff have?**

**Solution:**
First of all, when we know that with nine equal rows
he had none leftover we know that it has to be a multiple of 9.
We begin to solve the problem by writing multiples
of 9

9

18

27

36

45
We can cross 45 off because when you divide it by 5
there is no remainder. According to our problem if we have five
equal rows we need to have one left over.
54

63

72

81
Divide 81 by 5 and you get a remainder of 1...that
works!

Divide 81 by 4 and we get a remainder of 1...that works!

Divide this by 9 and, of course, we get a remainder of 0...this
works!

**Therefore, Jeff has 81 blocks.**

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