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Patterns - Number Patterns

Grade 5CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Growing Patterns: These are sequences where each number increases by a fixed rule. For example, in 4,8,12,164, 8, 12, 16, each term increases by 44. Visually, imagine a staircase where each step is 44 units higher than the previous one.

Square Numbers: A square number is the result of multiplying a whole number by itself (e.g., 3×3=93 \times 3 = 9). Visually, these numbers can be arranged as dots in a perfect square grid with an equal number of rows and columns, such as a 4×44 \times 4 grid representing 1616.

Triangular Numbers: These are numbers that can form an equilateral triangle. The sequence is 1,3,6,10,15,1, 3, 6, 10, 15, \dots. Visually, you can build this by starting with 11 dot, then adding a row of 22 dots underneath, then a row of 33, and so on (1,1+2,1+2+31, 1+2, 1+2+3, etc.).

Magic Squares: A magic square is a 3×33 \times 3 grid of numbers where the sum of each row, each column, and both diagonals is the same constant value. Visually, it looks like a sudoku-style grid where every direction adds up to the same 'Magic Sum'.

Number Towers/Pyramids: In this pattern, numbers are stacked in blocks. The value of any block is equal to the sum of the two blocks directly underneath it. Visually, it looks like a brick wall where each brick rests on two bricks from the row below.

Fibonacci-like Patterns: This is a sequence where each number is the sum of the two numbers before it. For example, in 2,3,5,8,132, 3, 5, 8, 13, we see 2+3=52+3=5 and 5+8=135+8=13. Visually, this pattern is often seen in the growth of flower petals or spiral shells.

Patterns in Odd and Even Numbers: There are specific rules for sums: Even+Even=EvenEven + Even = Even, Odd+Odd=EvenOdd + Odd = Even, and Odd+Even=OddOdd + Even = Odd. For example, 3(Odd)+5(Odd)=8(Even)3 (Odd) + 5 (Odd) = 8 (Even).

Coding and Decoding: Patterns can be used to hide messages by assigning numbers to letters (e.g., A=1,B=2,C=3A=1, B=2, C=3). A pattern like 'Add 2' would change 'A' into 33 (C). Visually, this is like a translation table where one set of symbols maps to another.

📐Formulae

Square Number=n×nSquare\ Number = n \times n

Magic Sum (3×3)=3×Middle NumberMagic\ Sum\ (3 \times 3) = 3 \times \text{Middle Number}

Sum of first n odd numbers=n×nSum\ of\ first\ n\ odd\ numbers = n \times n

Triangular Number=n×(n+1)2Triangular\ Number = \frac{n \times (n + 1)}{2}

Next Term=Previous Term+Common DifferenceNext\ Term = Previous\ Term + Common\ Difference

💡Examples

Problem 1:

Identify the pattern rule and find the next two terms in the sequence: 1,4,9,16,1, 4, 9, 16, \dots

Solution:

Step 1: Check the differences between terms. 41=34-1=3, 94=59-4=5, 169=716-9=7. The differences are 3,5,73, 5, 7. \ Step 2: Alternatively, observe that 1=1×11 = 1 \times 1, 4=2×24 = 2 \times 2, 9=3×39 = 3 \times 3, and 16=4×416 = 4 \times 4. \ Step 3: These are Square Numbers. The next term is 5×5=255 \times 5 = 25. \ Step 4: The term after that is 6×6=366 \times 6 = 36.

Explanation:

This sequence follows the rule of square numbers, where each term nn is calculated as n×nn \times n.

Problem 2:

Complete the Number Tower where the bottom row has the numbers 10,20,3010, 20, 30.

Solution:

Step 1: Calculate the middle row. The first block is 10+20=3010 + 20 = 30. The second block is 20+30=5020 + 30 = 50. \ Step 2: Calculate the top block by adding the two blocks from the middle row: 30+50=8030 + 50 = 80. \ Step 3: The final tower has 8080 at the top, 3030 and 5050 in the middle, and 10,20,3010, 20, 30 at the bottom.

Explanation:

In a number tower, you work from the bottom up by summing adjacent blocks to find the value of the block resting on them.