Question

2. What is the sum of all the two-digit positive integers whose units digit is 3?​

Answer 1

Answer:

the only number whose square ends in a 1 is a number that ends in 9 or 1

so a quick check on my trusty calculator and squaring numbers like 11,21,31,..91,19,29,39,..99

showed me

51^2 = 2601

49^2 = 2401.

99^2 = 9801

the sum of these 3 is 199

Step-by-step explanation:

Kindly Mark Me As Brainiest bro

Answer 2

Answer:

3+13+23 +33+43+53+63+73+83+93

here a= 3,d= 10

Sn= a(first + last term )/2

3/2(96)

3 X 48