the sum of all two digit order number is Question the sum of all two digit order number is in progress 0 Math Adeline 2 months 2021-08-11T14:43:39+00:00 2021-08-11T14:43:39+00:00 2 Answers 0 views 0

## Answers ( )

Step-by-step explanation:Sum of ‘n’ numbers is

Sn = n/2 (2a+(n-1)d)

first 2 digit number = 10, difference between any 2 successive numbers = 1, last number= 99, no.of digits from 10 to 99 = 90

Sn = 90/2 [2(10)+(90-1)1]

Sn = 45[20+89]

Sn = 45[109]

Sn = 4905

therefore, sum of all 2 digit numbers = 4905

2nd method:

Sn = n/2 [a+l]

first 2 digit number (a) = 10, last number(l) = 99, no.of digits from 10 to 99 = 90

Sn = 90/2 [10+99]

Sn = 45(109)

Sn = 4905

Answer:ok

Step-by-step explanation:dont know dkfjsksknzkjkdJJrxfsa0

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