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Play with Patterns - Number Patterns

Grade 4CBSE

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

🔑Concepts

Number Patterns: A number pattern is a sequence of numbers that follows a specific rule. For example, in the pattern 2,4,6,8,102, 4, 6, 8, 10, each number increases by 22. Visualizing this on a number line, you would see equal-sized 'jumps' of 22 units between each number to reach the next term.

Increasing Patterns: These are patterns where the numbers grow larger by adding or multiplying a specific value. For instance, in 3,6,12,243, 6, 12, 24, each number is multiplied by 22. Visually, this looks like a staircase where each step gets significantly taller than the previous one as you move from left to right.

Decreasing Patterns: These patterns show numbers getting smaller through subtraction or division. For example, in 100,90,80,70100, 90, 80, 70, we subtract 1010 each time. On a graph or chart, this would be represented by a series of points or bars that slope downwards in a straight line.

Growing Patterns: In these patterns, the amount being added or subtracted changes in a predictable sequence. For instance, in 1,2,4,7,111, 2, 4, 7, 11, the jumps are +1,+2,+3,+4+1, +2, +3, +4. Visually, if you represented these numbers with dots, you would see a shape (like a triangle) that expands by adding a longer row at the bottom each time.

Number Towers: A number tower is a pyramid-shaped arrangement of boxes. The rule is that the number in any box is the sum of the two numbers in the boxes directly below it. If you look at a tower with three levels, the single box at the very top is the final sum of the values layered beneath it.

Magic Squares: A magic square is a grid (often 3×33 \times 3) where the sum of numbers in every horizontal row, every vertical column, and both diagonals is exactly the same. Visually, no matter which straight line you draw through the grid, the numbers on that line will add up to a 'Magic Sum.'

Coding and Decoding: Number patterns are used in secret messages by assigning each letter of the alphabet a specific number (e.g., A=1,B=2,,Z=26A=1, B=2, \dots, Z=26). This creates a pattern where words like 'BAG' are converted into the sequence 2,1,72, 1, 7. Decoding involves reversing this pattern to find the original words.

📐Formulae

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

Next Term=Current Term×Common MultipleNext \ Term = Current \ Term \times Common \ Multiple

Sum of first nn odd numbers: 1+3+5+=n×n1 + 3 + 5 + \dots = n \times n

Magic Sum for 3×33 \times 3 grid: Magic Sum=3×Middle NumberMagic \ Sum = 3 \times Middle \ Number

💡Examples

Problem 1:

Find the next two numbers in the pattern: 5,11,17,23,,5, 11, 17, 23, \dots, \dots

Solution:

  1. Find the difference between the first two numbers: 115=611 - 5 = 6. \n2. Check the difference between the next pair: 1711=617 - 11 = 6. \n3. The rule is to add 66 to the current number. \n4. Next number: 23+6=2923 + 6 = 29. \n5. Following number: 29+6=3529 + 6 = 35.

Explanation:

This is an increasing arithmetic pattern where a constant value of 66 is added to each term to find the next one.

Problem 2:

Complete the Number Tower if the bottom row contains the numbers 10,20,3010, 20, 30.

Solution:

  1. Bottom Row: 10,20,3010, 20, 30. \n2. Middle Row (sum of adjacent bottom boxes): \n Box 1: 10+20=3010 + 20 = 30 \n Box 2: 20+30=5020 + 30 = 50 \n3. Top Row (sum of the two middle boxes): \n Top Box: 30+50=8030 + 50 = 80.

Explanation:

In a number tower, we work from the bottom up by adding pairs of adjacent numbers to determine the value of the box resting on top of them.