Missing Numbers

One dark and mysterious night, Sandy and David heard screams from their neighbor’s house. They ran over to see why they were screaming. Sandy and David found their neighbor clutching a calendar. "Someone has stolen numbers from our calendar and our clock. Please help us find our numbers!" they declared.

Sandy looked at the numberless clock while David looked around the room. David shouted, " I found some numbers laying on the table by the window. They seem to be in some kind of sequence."

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Sandy notices how the numbers are put in a certain sequence. "It seems that every other number is missing. If the numbers on the table were to continue in a sequence, it would look like this."

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39….

Notice how one number is missing between each of these numbers!

Sandy and David begin to investigate the almost numberless calendar. The numbers left on the calendar are:
2 5 8 14 17 23 26

"There seems to be another sequence", David states.
"I agree. There are two numbers missing between every number that was left. Hey! There are three numbers missing from the sequence!"

Calling all detectives out there. We need your help to find the missing numbers in the sequence.

Select the missing numbers.

2 5 8 14 17 23 26

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Apparently the person (or creature) who took the numbers has created number sequences and placed them all around the house. It appears that he has kept some of the numbers for himself. Please help Sandy and David find the missing numbers in each of these number sequences. You may even find out who took the numbers to begin with.

Numbers were found: in the kitchen

3, 7, 11, , 15, , 23
In the living room;

20, 22, 24, , 28,

In the bathroom;

12, 15, , 21, , 27

and in the bedroom.

, 10, 15, ,, 30

Numbers were found: in the kitchen

3, 7, 11, , 19, , 27

Patterns can be found in many places. Sometimes we may find more than one pattern. Look at this example.

2, 4, ? What is the next number?

Now what about this sequence?

2, 4, 6,

A pattern must be repeated at least twice to know what it REALLY is.

Fill in the missing numbers in each sequence. YOU MAY WANT TO WRITE THE ANSWERS DOWN ON PAPER BEFORE TYPING IN THE ANSWERS.

2, 4, 6, , , 12, 14

3, 6, 9, , 15, , 21

, 8, 12, 16, 20, 24,

, , 15, 20, 25,

20, 30, 40, , 60,

4, 7, 10, , 16, 19, 22, , 28,

11, 22, 33, , 55, , , 88, 99

205, 210, 215, 220, , , , 240

100, 102, 104, , , 110, 112, , 116

Now let’s take what we have learned about sequences and put it to some good use.

Line up a row of quarters, dimes, and nickels with six in each row on a sheet of paper. Write the value of the first coin below it on the paper. Add the next coin to the first and write the answer below the second coin. Do this until you have completed each row.

Did you notice that there was a sequence?

How many numbers are missing between each number on the first row of quarters? Dimes? Nickels?

HAVE FUN J