Each X value is multiplied by  to get the Y value. 

To find the rule, you may have to do some trial and error. The most important thing to remember is, once you think you have the rule, make sure to test the rule with all of the X values. 

Each X value is multiplied by  to get the Y value. 

To find the rule, you may have to do some trial and error. The most important thing to remember is, once you think you have the rule, make sure to test the rule with all of the X values. 

The first step in solving this problem is identifying the pattern used to create the sequence. It could be any of the four operations (addition, subtraction, multiplication, or division). 

The first thing that may be noticed is that the numbers are increasing, which would likely mean the pattern is using addition or multiplication because this leads to larger numbers in the answer rather than smaller answers.

Let's focus on multiplication first, 1x____=5 would be the first step to see if multiplication is the pattern being used. 1x5=5, so this could be our pattern. We must try the rule again with the next digit to see if it follows in sequence. 5x5=25, which is larger than the last number (13) in the series, so multiplication is not the operation used. We can eliminate multiplication.

This leaves us with addition. 1+___=5 reveals that 4 can be added to make 5. To see if the pattern holds, we can try it with 5+4=9 and then use the sum from the attempted pattern to try and make 13. 9+4=13, so we see that 4 works again. This means that the rule is to add each number by 4 to reveal the next number in the sequence.

The missing number in the sequence is 9.

The first step in solving this problem is identifying the pattern used to create the sequence. It could be any of the four operations (addition, subtraction, multiplication, or division). 

The first thing that may be noticed is that the numbers are decreasing, which would likely mean the pattern is using subtraction or division because this leads to smaller numbers in the answer rather than larger answers.

Let's focus on division first, 16÷____=12 would be the first step to see if division is the pattern being used. There is no whole number that would give 12 as the quotient to this problem, so with that, we can eliminate division.

This leaves us with subtraction. 16-___=12 reveals that 4 can be subtracted to make 12. To see if the pattern holds, we can try it with 12-___=8 and 4 works again. This means that the rule is to subtract each number by 4 to reveal the next number in the sequence.

8-4=4 so the missing number in the sequence is 4.

The first step in solving this problem is identifying the pattern used to create the sequence. It could be any of the four operations (addition, subtraction, multiplication, or division). 

Something that may be noticed is that the numbers are decreasing, which would likely mean the pattern is using subtraction or division because this leads to smaller numbers in the answer rather than larger solutions.

Let’s focus on subtraction first, 500-____=100 would be the way to identify the difference between the two numbers and a possible rule. 500-400=100, so the next term would need to be subtracted by 400 to make this rule accurate. 100-400 is NOT 20, so subtraction cannot be the pattern.

This leaves us with division. 500÷___=100 reveals that 5 can be inserted into the blank to make 100. 500÷5=100 is true. To see if the pattern holds, we can try it with 100÷5=20, and it works again. The final test is with the last number in the sequence, 20÷5=4, so the rule holds. Dividing by 5 will get the next term in the series.

The rule is to divide each term by 5.