Sequences / Skips

🏆Practice sequences / skips up to 100

Sequences / Skips

When we have a sequence -
1) We read it from left to right
2) We understand if it's increasing or decreasing
3) We examine which digit type changes
4) We determine the pattern of the sequence
5) We complete the sequence according to the pattern that we discovered

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Test yourself on sequences / skips up to 100!

einstein

Complete the following sequence:

\( 1,3.\ldots \)

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Sequences / Skips

What is an arithmetic sequence?

Numbers that come one after another with equal intervals between them.
The sequence can increase and the sequence can also decrease.

How can we determine whether the sequence is increasing or decreasing?

Always read the sequence from left to right! Just like reading a number.
Let's see what number it starts with and what number it ends with.
If the first number is smaller than the last number - there is an increase - ascending sequence
If the first number is larger than the last number - there is a decrease - descending sequence

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How can we determine what the pattern of the sequence is?

In order to discover a pattern, let's remember the rules we learned:
A number has ones, tens, and hundreds digits
For example -
57125712
22= ones digit
11 = tens digit
77 = hundreds digit
55= thousands digit

When we encounter a sequence - we ask ourselves -
In which digit did the change occur? Ones/Tens/Hundreds/Thousands
When we know which digit changed, we can immediately identify the intervals between the numbers and discover the pattern - adding or subtracting...
Let's look at a sample number sequence:
5,6,7,8,9,105,6,7,8,9,10
The sequence before us is an increasing sequence -
A sequence that starts at 55
and increases up to 1010.

There are intervals of 1 between each number 11
Therefore we can determine that:
The pattern of the sequence is 11.

Let's look at the following sequence:
13,15,17,1913,15,17,19

Let's check - whether the sequence increasing or decreasing -
The first number is 1313
and the last number is 1919
There is an increase, therefore the sequence is increasing.

Which digit changes? The ones digit.
How much does it change by each time? 22.
The pattern is – adding 22

Another example:
Let's explore the following sequence -
213,223,233,243,253213,223,233,243,253
Let's check if the sequence is increasing or decreasing
The first number is 213213
The last number is 253253
There is an increase hence the sequence is increasing.
Let's check in which digit the change occurs -
The change occurs in the tens digit
Each time 1010 is added
Therefore the pattern is - adding 1010.

Another example -
650,550,450,350650,550,450,350
Let's check if the sequence is increasing or decreasing -
The first number is 650650
The last number is 350350
There is a decrease hence the sequence is decreasing.
Let's check in which digit the change occurs and examine the change -
The change occurs in the hundreds digit - each time decreasing by 100100
Therefore the pattern is - subtraction of 100100

Now let's practice!
Look at the following sequence,
Complete it and determine:
Is the sequence increasing or decreasing?
What is its pattern?
102,___,122,132,142102, \_\_\_,122,132,142

Solution
Note –
In order to complete the sequence, we will first examine it and understand whether it is increasing or decreasing and what the pattern is.
We see that the first number in the sequence is 102102
and the last number in the sequence is 142142.
There is an increase, hence the sequence is increasing.
Now let's check from the numbers we have in which digit the change occurs – in the tens digit.
We can see that each time the number increases by 1010
Therefore- the pattern is adding 1010.
Now let's complete the sequence:
If we determined that the pattern is adding 1010, all we need to do is add 1010
to the number 102102
We obtain the following:
102+10=112102+10=112
Let's complete the sequence:
102,112,122,132,142102, {\underline{112}}, 122,132,142

Another exercise:
Complete the following sequence,
determine whether it is increasing or decreasing and indentify its pattern.
130,___,70,___,30,10130, \_\_\_, 70, \_\_\_,30,10

Solution:
First, let's understand whether the sequence is increasing or decreasing.
The first number in the sequence is 130130
The last number is 1010
There is a decrease, therefore the sequence is decreasing.

Let's examine in which digit the change occurs - the change occurs in the tens digit.
We observe that in every 2 numbers the number decreases by 2020.
Therefore, the pattern is - subtraction of 2020.
Now that we have discovered the pattern, all we need to do is complete the sequence.
In order to determine which number comes after 110110, we subtract 2020 and obtain :
11020=90110-20=90
In order to determine which number comes after 7070, we subtract 2020 and obtain the following:
7020=5070-20=50
Let's complete the sequence:
130,110,90,70,50,30,10130, 110, {\underline {90}}, 70, {\underline {50}}, 30, 10

Do you know what the answer is?

Examples with solutions for Sequences / Skips up to 100

Exercise #1

Complete the following sequence:

1,3. 1,3.\ldots

Step-by-Step Solution

To solve this problem, we need to identify the pattern in the sequence provided, which initially lists the numbers 1 1 and 3 3 .

First, observe the given numbers: 1 1 and 3 3 .

The difference between the first term 1 1 and the second term 3 3 is:
31=2 3 - 1 = 2 .

This suggests a common difference of 2 2 , implying that the sequence is likely an arithmetic sequence where each term increases by 2 2 .

We can use this observation to predict the next terms in the sequence:

  • Starting with 1 1 , add the common difference 2 2 :
    1+2=3 1 + 2 = 3 .
  • From 3 3 , add the common difference 2 2 :
    3+2=5 3 + 2 = 5 .
  • Continuing this pattern, from 5 5 , add 2 2 :
    5+2=7 5 + 2 = 7 .
  • And from 7 7 , add the common difference 2 2 :
    7+2=9 7 + 2 = 9 .

Thus, the sequence can be extended as:
1,3,5,7,9 1, 3, 5, 7, 9 .

From the possible choices, the correct sequence is represented by choice 4.

Therefore, the correct answer to the problem is 1,3,5,7,9 1, 3, 5, 7, 9 .

Answer

1,3,5,7,9 1,3,5,7,9

Exercise #2

Complete the following sequence:

5,7 5,7\ldots

Step-by-Step Solution

To solve this problem, we'll identify whether the sequence follows a recognizable pattern. The sequence so far is 5,75, 7.

Let's determine whether it follows an arithmetic sequence:

  • First Term (a1a_1) = 5
  • Second Term (a2a_2) = 7
  • The Common Difference (dd) = 75=27 - 5 = 2

Assuming a consistent common difference, the sequence appears to be an arithmetic sequence increasing every term by 2.

Let's calculate the next few terms:

  • Third Term (a3a_3) = 7+2=97 + 2 = 9
  • Fourth Term (a4a_4) = 9+2=119 + 2 = 11
  • Fifth Term (a5a_5) = 11+2=1311 + 2 = 13

Thus, the full sequence is: 5,7,9,11,135, 7, 9, 11, 13.

A review of the multiple-choice options shows that the correct answer is given by choice 1: 5,7,9,11,135, 7, 9, 11, 13.

Therefore, the complete sequence is 5,7,9,11,135, 7, 9, 11, 13.

Answer

5,7,9,11,13 5,7,9,11,13

Exercise #3

Complete the following sequence:

25,,21,19,, 25,\ldots,21,19,\ldots,\ldots

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Determine the common difference by looking at the known terms, 21 and 19.
  • Step 2: Apply the common difference to find the missing terms in the sequence.
  • Step 3: Verify the sequence pattern to ensure accuracy.

Now, let's work through each step:

Step 1: The common difference between 21 and 19 is 2. Thus, each number in the sequence is reduced by 2 from the previous one.

Step 2: Starting from 25, subtract 2 to fill in the first gap: 252=23 25 - 2 = 23 . Now the sequence is 25, 23, ..., 21, 19.

From 19, subtract 2 to fill in the next gap: 192=17 19 - 2 = 17 , then 172=15 17 - 2 = 15 . Thus, the complete sequence is:

25,23,21,19,17,15 25, 23, 21, 19, 17, 15

Therefore, the solution to the problem is 25,23,21,19,17,15 25, 23, 21, 19, 17, 15 .

Answer

25,23,21,19,17,15 25,23,21,19,17,15

Exercise #4

Complete the following sequence:

20,,24,26, 20,\ldots,24,26\ldots ,\ldots

Step-by-Step Solution

To solve the problem of completing the sequence 20,,24,26,, 20, \ldots, 24, 26, \ldots, \ldots , we recognize the sequence's underlying pattern.

Step 1: Analyze known terms.
The given sequence begins with 20,,24,26,, 20, \ldots, 24, 26, \ldots, \ldots . Notice the known terms 20 20 and 24 24 , and 26 26 .

Step 2: Determine the difference between known terms.
The difference between 24 24 and 20 20 is 4 4 , suggesting an ongoing pattern.
Between 26 26 and 24 24 , the difference is 2 2 , proposing alternation in differences or a complete oversight of interspersed terms around 26 26 .

Step 3: Determine full sequence consistency.
Check if numbers align with a two-step even-number sequence, which implies adding 2 2 successively.
Extending forward and back confirms 20,22,24,26,28, 20, 22, 24, 26, 28, \ldots .

Step 4: Verification considering other instructions.
The sequence appears to be a straightforward arithmetic one comprising purely even numbers beginning from 20 20 . This step requires confirming subsequent numbers 28,30 28, 30 .

Conclusion: Sequential confirmation proves the arithmetic nature of the understanding, yielding:

20,22,24,26,28,30 20,22,24,26,28,30

Answer

20,22,24,26,28,30 20,22,24,26,28,30

Exercise #5

Complete the sequence:

36,34 36,34\ldots

Step-by-Step Solution

To complete the given sequence 36,34, 36, 34, \ldots , we need to identify the pattern in the sequence. From the given terms, it appears that the sequence is decreasing.

Let's check if this is an arithmetic sequence, where each term decreases by a constant amount:

  • Subtract the second term from the first term: 3634=2 36 - 34 = 2 .
  • This indicates that each term is decreasing by 2.

Recognizing this pattern, the sequence can be continued by subtracting 2 from each subsequent term:

  • The next term after 34 is calculated as follows: 342=32 34 - 2 = 32 .
  • Continuing, the term after 32 is: 322=30 32 - 2 = 30 .
  • Finally, the term following 30 is: 302=28 30 - 2 = 28 .

Therefore, the complete sequence is 36,34,32,30,28 36, 34, 32, 30, 28 .

The correct answer choice, which matches this sequence, is:

36,34,32,30,28 36,34,32,30,28

Answer

36,34,32,30,28 36,34,32,30,28

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