1+2+3+4=10
(10 + 1) x 10/2
-946515634175
The formula for volume is 1/3 Bh ( 1/3 pi times radius squared times the height.) The formula for surface area is 2 pi r h plus 2 pi r squared.
1+2+3+4=10 The formula for adding consecutive numbers is n*(n+1)/2. This could be done easily as mental math, on paper or using a calculator.
1 + 2 + 3 = 6
43
1 + 2 + 3 + 4.1 = 10.1
1 + 2 + 3 + 4.99 = 10.99
2/3 plus 2/3 equals 4/3 or 1 1/3.
It is 77
23
-1