| Isaac Dalby - Mathematics - 1806 - 526 pages
...x : Euler however, has found the theorem 32 defective when x — 32, for 2 + 1 = 641 x 6700117815. If the sum of the digits of a number is divisible by 9, the number itself is also divisible by 9. Let a, b, c, d, be the digits of a number consisting of 4 figures ;... | |
| Isaac Dalby - Mathematics - 1807 - 968 pages
...however, has found the theorem 32 -»• •' * defective when x = 33, for 8 + 1 = 641 x 6700417« 815. If the sum of the digits of a number is divisible by g, the number itself is also divisible by 9. Let a, b, t, d, be the digili of a number consisting of... | |
| Andrew Bell (writer on mathematics.) - 1839 - 500 pages
...when N is divided by 9, is the remainder when a + 5 + c + <Z+...is divided by 9. (445.) 1 Hence when the sum of the digits of a number is divisible by 9, so is the number itself.1 The same property belongs to the number 3. (446.) 1 The remainder, on dividing... | |
| Charles Davies, William Guy Peck - Electronic book - 1855 - 592 pages
...formulas, in which / denotes the length of the edge, s the area of the surface, and в the volume : 5. If the sum of the digits of a number is divisible by cither 3. or 9, the number itself will also be divisible by the same number, 3 or 9 6. If a number... | |
| Noble Heath - Arithmetic - 1856 - 472 pages
...by the three right-hand figures of a number, 8 mtasures the number. 8. When the sum of the figures of a number is divisible by 9, the number is divisible by 9, (113.) Also, the difference between a number and the same number reversed, is, when n»ta, cypher,... | |
| James Stewart Eaton - Arithmetic - 1857 - 376 pages
...Division by casting out the 9's are founded. (g) The properties given for 9 are equally true for 3 ; ie if the sum of the digits of a number is divisible by 3, the number is itself divisible by 3, and if the sum of the digits divided by 3 gives a remainder,... | |
| Ireland commissioners of nat. educ - 1865 - 184 pages
...When the three right-hand figures are divisible by 8 the whole number is divisible by 8. 6th. When the sum of the digits of a number is divisible by 9 the sum itself is divisible by 9 or 3. 7th. When the sum of the digits of a number is divisible by 3 the... | |
| William Guy Peck - Arithmetic - 1877 - 430 pages
...3.136. NOTE. — If the final digit of a number is 0, 2, 4, 6, or 8, the num ber is divisible by 2. If the sum of the digits of a number is divisible by 3, the number itself is divisible by 3. If the final digit of a number is 5, the number is divisible... | |
| Alexander Kennedy Isbister - 1882 - 190 pages
...When the three right.hand figures are divisible by 8 the whole number is divisible by 8. ,•т. When the sum of the digits of a number is divisible by 9 the mm itself is divisible by 9 or 8. 7th. When the sum of the digits of a number is divisible by 3 the... | |
| John Alexander Luman - Arithmetic - 1914 - 366 pages
...right-hand figures of a given number, the given number is divisible by 8. 7. When the sum of the figures of a number is divisible by 9, the number is divisible by 9. 8. 1001 and its multiples, which are usually easily recognized, are divisible by 7, 11, and IS. 9.... | |
| |