 # Adding a Sequence of numbers (Pairing Method)

## Presentation on theme: "Adding a Sequence of numbers (Pairing Method)"— Presentation transcript:

Adding a Sequence of numbers (Pairing Method)
1. Find the sum of …… Problem Solving Strategy :- Step 1 – Divide the last number by 2 50 ÷ 2 = 25{ to get the numbers of pairs } Step 2 – Add 1 to the last number ( 50 ) = 51 { The sum of each pair is 51 } Step 3 – Multiply the results from steps 1 and 2 : 25 x 51 = 1275

Adding a Sequence of numbers (Pairing Method)
Now you try : - 2. Find the sum of …… What if the sequence of numbers that does not end with even numbers? Now you try : - 3. Find the sum of …… Now you try : - 4. Find the sum of ……

Adding a Sequence of numbers (Triangle Method)
1. Find the sum of …… Problem Solving Strategy :- Step 1 – Multiply the last number (50) by the next higher number (51) and divide the product by 2. 50 x 51 ÷ 2 = 1275 Now you try : - 2. Find the sum of ……

Adding a Sequence of numbers (Average Method)
What if the sequence of consecutive number does not start with 1? 1. Find the sum of …… Problem Solving Strategy :- Step 1 – Subtract the first number from the last number and add 1 (50 – 11) + 1 = 40{ to get the numbers of Terms } Step 2 – Add the first number to the last number and divide the result by 2. ( ) ÷ 2 = 30.5 { The average is 30.5 } Step 3 – Multiply the results from steps 1 and 2 : 40 x 30.5 = 1220 Now you try : - 2. Find the sum of ……

Adding a Sequence of numbers (Average Method)
Now you try : - 3. Find the sum of …… Now you try : - 4. Find the sum of ……

Adding a Sequence of odd numbers
1. Find the sum of …… Problem Solving Strategy :- Step 1 – Add 1 to the last number and divide the last number by 2 (1 + 51)÷ 2 = 26{ to get both the Average and the numbers of Terms } Step 2 – Square the results from step 1. 26 x 26 = 676 Now you try : - 2. Find the sum of ……

Adding a Sequence of odd numbers
What if the sequence of consecutive number does not start with 1? 1. Find the sum of …… Problem Solving Strategy :- Step 1 – Subtract the first number from the last number, divide it by 2 and add 1 (33 – 7) ÷ = 14{ to get the numbers of Terms } Step 2 – Add the first number to the last number and divide the result by 2. (7 +33) ÷ 2 = 20 { The average is 20 } Step 3 – Multiply the results from steps 1 and 2 : 14 x 20 = 280 Now you try : - 2. Find the sum of ……

Adding a Sequence of even numbers
1. Find the sum of …… Problem Solving Strategy :- Step 1 – Divide the last number by 2 50 ÷ 2 = 25{ to get the numbers of Terms } Step 2 – Add 2 to the last number and divide the sum by 2. (50 + 2) ÷ 2 = 26 {to get the average} Step 3 – Multiply the results from steps 1 and 2 25 x 26 = 650 Now you try : - 2. Find the sum of ……

Adding a Sequence of even numbers
What if the sequence of consecutive number does not start with 2? 1. Find the sum of …… Problem Solving Strategy :- Step 1 – Subtract the first number from the last number, divide it by 2 and add 1 (34 – 8) ÷ = 14{ to get the numbers of Terms } Step 2 – Add the first number to the last number and divide the result by 2. (8 +34) ÷ 2 = 21 { The average is 20 } Step 3 – Multiply the results from steps 1 and 2 : 14 x 21 = 294 Now you try : - 2. Find the sum of ……