Answer:
45
Step-by-step explanation:
2 digit number starts from 10 ends at 99
between 10 and 19 there is only one number whose tens digit is more than ones digit.
that is 10
between 20 and 29 there are two numbers
20 and 21
like the same
between 30 and 39 there are 3 numbers
10–19. 1
20–29. 2
30–39. 3
40–49. 4
50–59. 5
60–69. 6
70–79. 7
80–89. 8
99–99. 9
sum of first n natural numbers is n(n+1)/2
9(9+1)/2=45
Answer:
The length of the circumference is
or 
Step-by-step explanation:
<u><em>The question in English is</em></u>
On a court, the central circumference will be painted, which has a diameter of 5 m. What is the length of the circumference?
we know that
The circumference of a circle is given by the formula

we have

substitute

This is the exact value
assume


Answer:
35 and communitive property
Step-by-step explanation:
on edg 2021
D. 15 in (my work is shown in the attached photo)