138 including 1 and 2 digit numbers.
-- I'll assume that we're only talking about whole numbers, and no decimals or fractions.
-- The number can't have more than 3 digits. If it had four, it would be more than 1,000.
-- One-digit numbers . . . 6 possibilities, all less than 350.
-- Two-digit numbers . . . 6 x 6 = 36 possibilities, all less than 350.
-- In three-digit numbers . . .
. . . the first digit can be 1, 2, or 3.
. . . If the first digit is 3, then the second one can be 1, 2, 3, or 4 = 4 choices.
. . . . . . For each of the 4 choices, the third digit can be 1, 2, 3, 4, 5, or 6 = 6 choices.
. . . . . . Total possibilities beginning with a 3 . . . 4 x 6 = 24
. . . If the first digit is 1 or 2, then
. . . . . . the second digit can be 1, 2, 3, 4, 5, or 6 = 6 choices. For each one . . .
. . . . . . the third digit can be 1, 2, 3, 4, 5, or 6 = 6 choices.
. . . . . . Total possibilities beginning with 1 or 2 . . . 2 x 6 x 6 = 72
Adam up:
One-digit possibilities . . . . . . . . . . . . . . . . . . . . . . 6
Two-digit possibilities. . . . . . . . . . . . . . . . . . . . . . 36
Three-digit possibilities beginning with 3. . . . . . . 24
Three-digit possibilities beginning with 1 or 2 . . . 72
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
-- I'll assume that we're only talking about whole numbers, and no decimals or fractions.
-- The number can't have more than 3 digits. If it had four, it would be more than 1,000.
-- One-digit numbers . . . 6 possibilities, all less than 350.
-- Two-digit numbers . . . 6 x 6 = 36 possibilities, all less than 350.
-- In three-digit numbers . . .
. . . the first digit can be 1, 2, or 3.
. . . If the first digit is 3, then the second one can be 1, 2, 3, or 4 = 4 choices.
. . . . . . For each of the 4 choices, the third digit can be 1, 2, 3, 4, 5, or 6 = 6 choices.
. . . . . . Total possibilities beginning with a 3 . . . 4 x 6 = 24
. . . If the first digit is 1 or 2, then
. . . . . . the second digit can be 1, 2, 3, 4, 5, or 6 = 6 choices. For each one . . .
. . . . . . the third digit can be 1, 2, 3, 4, 5, or 6 = 6 choices.
. . . . . . Total possibilities beginning with 1 or 2 . . . 2 x 6 x 6 = 72
Adam up:
One-digit possibilities . . . . . . . . . . . . . . . . . . . . . . 6
Two-digit possibilities. . . . . . . . . . . . . . . . . . . . . . 36
Three-digit possibilities beginning with 3. . . . . . . 24
Three-digit possibilities beginning with 1 or 2 . . . 72
Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
138 including 1 and 2 digit numbers.
It is 120 if the digits cannot be repeated.
823543
(5 x 4 x 3 x 2) = 120 of them, if no digit can be repeated.If digits can be repeated in the same number, then 3,125numbers can be formed.
81
There are 8*9*8*7*6*5*4 = 483840 numbers.
It is 120 if the digits cannot be repeated.
823543
99876
(5 x 4 x 3 x 2) = 120 of them, if no digit can be repeated.If digits can be repeated in the same number, then 3,125numbers can be formed.
81
There are 5! = 120 such numbers.
There are 8*9*8*7*6*5*4 = 483840 numbers.
36
6*6*3 = 108 numbers.
7
There are 7,290 different 4-digit numbers that can be formed from the digits 1-9 without repetition.
3897