1
How many times does the digit 1 occur in ten place in the numbers from 1 to 1000?
999-111=888 888 3 digit numbers can be made with numbers between 1 - 9
There are 9 1-digit numbers and 16-2 digit numbers. So a 5 digit combination is obtained as:Five 1-digit numbers and no 2-digit numbers: 126 combinationsThree 1-digit numbers and one 2-digit number: 1344 combinationsOne 1-digit numbers and two 2-digit numbers: 1080 combinationsThat makes a total of 2550 combinations. This scheme does not differentiate between {13, 24, 5} and {1, 2, 3, 4, 5}. Adjusting for that would complicate the calculation considerably and reduce the number of combinations.
There are 900 three-digit whole numbers between 1 and 1000
the right answer is 10 cause there is o,1,2,3,4,5,6,7,8,9 so there 10 numbers in total which have 1 digit
10,000
With 123 digits you can make 123 one-digit numbers.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
There are 2941 4-digit numbers such no two of its digits differ by 1.
There are 28706 such combinations. 5456 of these comprise three 2-digit numbers, 19008 comprise two 2-digit numbers and two 1-digit numbers, 4158 comprise one 2-digit number and four 1-digit numbers and 84 comprise six 1-digit numbers.
There are 9000 4 digit numbers Find 4 digit numbers that are all different from 1 find 4 digit numbers that are all different from 1 The thousands digit has 8 ways to choose, hundreds, tens, and units all have 9 ways => there are 8 x 9 x 9 x 9 = 5832 digits => 4 digit numbers contain at least 1 digit 1 = number of 4 digit numbers , the number of 4 digit numbers is different by digit 1 =9000 - 5832 = 3168 numbers