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

Practice Sequences / Skips up to 100

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

Exercise #6

Complete the sequence:

1113,1112,1111, 1113,1112,1111,\ldots

Step-by-Step Solution

The given sequence is 1113,1112,1111 1113, 1112, 1111 .

Let's analyze the sequence:

  • The first term is 1113 1113 .
  • The second term is 1112 1112 , which is 11131 1113 - 1 .
  • The third term is 1111 1111 , which is 11121 1112 - 1 .

It's evident that each term is decreasing by 1 1 from the previous term. Therefore, this sequence is an arithmetic sequence with a common difference of 1-1.

Given this information, we can continue the sequence by subtracting 1 from the last given term, 1111 1111 .

  • The next term is 11111=1110 1111 - 1 = 1110 .
  • Following that, 11101=1109 1110 - 1 = 1109 .
  • Finally, 11091=1108 1109 - 1 = 1108 .

Thus, the next three terms in the sequence are 1110,1109, 1110, 1109, and 1108 1108 .

Looking at the provided options, choice 4: 1110,1109,1108 1110, 1109, 1108 , is the correct continuation of the sequence.

Answer

1110,1109,1108 1110,1109,1108

Exercise #7

Complete the sequence:

1007,1008,1009, 1007,1008,1009,\ldots

Step-by-Step Solution

To solve this problem, we'll identify the pattern in the sequence:

  • Step 1: Identify the order and pattern of the sequence
  • Step 2: Follow the arithmetic pattern of adding the same number to the last term to find the next numbers
  • Step 3: List the next terms in the sequence

Now, let's work through each step:

Step 1: The sequence given is 1007, 1008, 1009. We observe that each number is 1 more than the previous one.
Step 2: Continuing this pattern, the next number after 1009 is 1009+1=1010 1009 + 1 = 1010 .
Step 3: Similarly, we calculate the next numbers: 1010+1=1011 1010 + 1 = 1011 and 1011+1=1012 1011 + 1 = 1012 .

Therefore, the sequence can be completed as: 1010,1011,1012 1010, 1011, 1012 .

Answer

1010,1011,1012 1010,1011,1012

Exercise #8

Complete the sequence:

20,000, 20,001, 20,002,  20{,}000,\ 20{,}001,\ 20{,}002, \ \ldots

Step-by-Step Solution

To solve this problem, we will continue the sequence 20,000,20,001,20,002, 20,000, 20,001, 20,002, \ldots by adding 1 to the last number provided.

  • Start with the last number in the sequence, which is 20,002 20,002 .
  • Step 1: Add 1 to 20,002 20,002 to get 20,003 20,003 .
  • Step 2: Add 1 to 20,003 20,003 to get 20,004 20,004 .
  • Step 3: Add 1 to 20,004 20,004 to get 20,005 20,005 .

Thus, the continuation of the sequence is 20,003,20,004,20,005 20,003, 20,004, 20,005 .

Therefore, the correct answer is choice 1: 20,003,20,004,20,005 20,003,20,004,20,005 .

Answer

20,003, 20,004, 20,005 20{,}003,\ 20{,}004,\ 20{,}005

Exercise #9

Complete the sequence:

60,50,30, 60,50,\ldots30,\ldots

Step-by-Step Solution

To solve this problem, we will identify and use the pattern within the given sequence:

  • Step 1: Start with the given numbers 60 60 and 50 50 .
  • Step 2: Calculate the difference between these two numbers. We have 6050=10 60 - 50 = 10 .
  • Step 3: Assume this difference will continue throughout the sequence. This assumption is necessary because it suggests a common arithmetic sequence structure.

Following these steps, we can complete the sequence:

First term is 60 60 .

Second term is 50 50 .

Based on the assumption of an arithmetic sequence with a common difference of 10 -10 :

Third term: 5010=40 50 - 10 = 40 .

Fourth term: 4010=30 40 - 10 = 30 .

Continuing this pattern:
Fifth term: 3010=20 30 - 10 = 20 .
Sixth term: 2010=10 20 - 10 = 10 .

Therefore, the complete sequence is 60,50,40,30,20,10 60, 50, 40, 30, 20, 10 .

Answer

60,50,40,30,20,10 60,50,40,30,20,10

Exercise #10

Complete the sequence:

20,30,40 20,30,40\ldots

Step-by-Step Solution

To complete the sequence 20,30,40, 20, 30, 40, \ldots , we need to determine the pattern.

  • Identify the pattern: Find the difference between successive terms.
  • Calculate the difference: 3020=10 30 - 20 = 10 and 4030=10 40 - 30 = 10 . The common difference is 10.
  • Continue the sequence using this pattern: Add 10 to the last given number to find the next number.
  • Extend the sequence:
    • The term after 40 is 40+10=50 40 + 10 = 50 .
    • The next term is 50+10=60 50 + 10 = 60 .
    • The next term is 60+10=70 60 + 10 = 70 .

Thus, the complete sequence is 20,30,40,50,60,70 20, 30, 40, 50, 60, 70 .

Therefore, the solution to the problem is 20,30,40,50,60,70 20, 30, 40, 50, 60, 70 , corresponding to choice 4.

Answer

20,30,40,50,60,70 20,30,40,50,60,70

Exercise #11

Complete the sequence:

955,1000,1005, 955,1000,1005,\ldots

Step-by-Step Solution

To solve this problem, let's follow these steps:

  • Step 1: Calculate the differences between consecutive terms of the sequence.
  • Step 2: Use the common difference to find the next terms.
  • Step 3: Verify the result with the provided answer choices.

Step 1: Calculate the differences:
The difference between the first and second terms is 1000955=451000 - 955 = 45.
The difference between the second and third terms is 10051000=51005 - 1000 = 5.

Step 2: Identifying that the sequence alternates increases, first by 45 and then by 5, we predict it continues by adding 5. Thus, extending the sequence, the next terms would be:
1005+5=10101005 + 5 = 1010,
1010+5=10151010 + 5 = 1015,
1015+5=10201015 + 5 = 1020.

Therefore, the next terms in the sequence are 1010,1015,1020 1010, 1015, 1020 .

Step 3: Verify against provided answer choices. The correct choice is:

1010,1015,10201010,1015,1020

The next numbers in the sequence are 1010,1015,1020 1010, 1015, 1020 .

Answer

1010,1015,1020 1010,1015,1020

Topics learned in later sections

  1. Consecutive numbers