How many phone numbers can be made if

How many phone numbers can be made if the first digit must be 1,

the second digit must be a number in the range 3-5,

the third digit must be a number in the range (6-9),

and the last seven digits can be any single digit number 0-9?

 1) For the first digit, we have only one choice -- we must choose a 1.
 2) For the second digit, we have three choicees -- we must choose 3, 4, or 5.
 3) For the third digit, we have four choices -- we can choose 6, 7, 8, or 9.
 4) For the fourth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
 5) For the fifth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
 6) For the sixth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
 7) For the seventh digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
 8) For the eighth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
 9) For the ninth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .
10) For the tenth digit, we have ten choices -- we can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 .

1 X 3 X 4 X 10 X 10 X 10 X 10 X 10 X 10 X 10 = 120 000 000  possible numbers.