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 Βιβλία Βιβλία Hence, the sum of a series of numbers in progression by difference is one half of the product of the number of terms by the sum of the first and last terms. An Introduction to Algebra Upon the Inductive Method of Instruction - Σελίδα 231
των Warren Colburn - 1831 - 276 σελίδες
Πλήρης προβολή - Σχετικά με αυτό το βιβλίο ## Ray's New Practical Arithmetic: A Rev. Ed. of the Practical Arithmetic

Joseph Ray - 1877 - 336 σελίδες
...product. 2. The extremes are 2 and 50; the number of terms, 24 : find the sum of the series. 624. 3. How many strokes does the hammer of a clock strike in 12 hours? . " 78. 4. Place 100 apples in a right line, 3 yd. from each other, the first, 3 yd. from a basket... ## Ray's New Higher Arithmetic: A Revised Edition of the Higher Arithmetic

Joseph Ray - 1880 - 408 σελίδες
...that of the extremes, and hence, as the above illustrates, the double of any such series is equal to the product of the number of terms by the sum of the extremes. FORMULA. — s =. (« + t) n. ~~2~ "Rale.— Multiply the sum of the extremes by the number... ## Practical Arithmetic, by Induction and Analysis, Βιβλίο 3

Joseph Ray - 1885 - 336 σελίδες
...series. 2. Tho extremes are 2 and 50 ; the number of terms, 24 : find the sum of the series. Ans, 624. 3. How many strokes does the hammer of a clock strike in 12 hours? Ans. 78. 4. Find the sum of the first ton thousand numbers in the series, 1, 2, 3, 4, 5, <fec. Ans.... ## An Arithmetic for Preparatory Schools, High Schools, and Academies

Charles Austin Hobbs - 1889 - 343 σελίδες
...terms of the series 24, 22£, 21, etc. 12. Find the sum of the odd numbers from 1 to 49 inclusive. 13. How many strokes does the hammer of a clock strike in 12 hours ? 14. How far can a man walk in 10 days, going 12 miles the first day, and increasing the rate 3 miles... ## A Practical Arithmetic

George Albert Wentworth - 1896 - 383 σελίδες
...Therefore, we have the following rule for finding the sum of an arithmetical progression : Take half the product of the number of terms by the sum of the first and last terms. Find the sum of nine terms of an arithmetical progression whose first term is 3 and last term 41. EXERCISE... ## A Practical Arithmetic

George Albert Wentworth - 1897 - 413 σελίδες
...Therefore, we have the following rule for finding the sum of an arithmetical progression : Take half the product of the number of terms by the sum of the first and last terms. Find the sum of nine terms of an arithmetical progression whose first term is 3 and last term 41. EXERCISE... ## Complete Arithmetic, Μέρος 2

George Wentworth - 1909
...the sum is J of 7 x 14, or 49. Therefore, to find the sum of an arithmetical progression, take half the product of the number of terms by the sum of the first and last terms. Thus the sum of nine terms of an arithmetical progression whose fust term is 3 and last term 41, is...