998,000
There are 5 numbers which can make the 3 digit numbers in this example. Therefore each digit in the 3 digit number has 5 choices of which number can be placed there. Therefore number of 3 digit numbers = 5 x 5 x 5 = 125
Multiplying by multi-digit numbers is similar to multiplying by two-digit numbers in that both processes involve breaking down the numbers into place values and multiplying each digit by each digit in the other number. The key similarity lies in the application of the distributive property, where each digit in one number is multiplied by each digit in the other number, and then the products are added together to get the final result. This process is consistent whether you are multiplying by a two-digit number or a multi-digit number.
-123456786
4 options for the first digit, 3 options for the second digit, 2 options for the third digit. Multiply the number of options together, and you find how many 3-digit numbers you can get.
998,000
There are 5 numbers which can make the 3 digit numbers in this example. Therefore each digit in the 3 digit number has 5 choices of which number can be placed there. Therefore number of 3 digit numbers = 5 x 5 x 5 = 125
There are four of each.
-123456786
4 options for the first digit, 3 options for the second digit, 2 options for the third digit. Multiply the number of options together, and you find how many 3-digit numbers you can get.
24 = 4*3*2*1 of them
61
the place of each digit help the value of the number by using your multuplication
For each number, there are four digits, and for each digit, there are two possibilities for digits: 3 or 4. So the number of 4-digit numbers is 2*2*2*2 = 16. The 4-digit numbers using 3 and 4 are: 3333 3334 3343 3344 3433 3434 3443 3444 4333 4334 4343 4344 4433 4434 4443 4444
6*5*4*3=360
Assuming that the first digit of the 4 digit number cannot be 0, then there are 9 possible digits for the first of the four. Also assuming that each digit does not need to be unique, then the next three digits of the four can have 10 possible for each. That results in 9x10x10x10 = 9000 possible 4 digit numbers. If, however, you can not use the same number twice in completing the 4 digit number, and the first digit cannot be 0, then the result is 9x9x8x7 = 4536 possible 4 digit numbers. If the 4 digit number can start with 0, then there are 10,000 possible 4 digit numbers. If the 4 digit number can start with 0, and you cannot use any number twice, then the result is 10x9x8x7 = 5040 possilbe 4 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.