I love these: T = tens place or first digit. U = ones place, units place, or second digit. 10T+U is the first number T+U=15 = T=15-U 10U+T is the number with the digits switched. 10U+T=10T+U+9 10U+15-U=10(15-U)+U+9 9U+15=150-10U+U+9 9U+15=159-9U 18U=144 U=8 T=15-8 T=7
The units digit of a two digit number exceeds twice the tens digit by 1. Find the number if the sum of its digits is 10.
9347 is not a digit but four digits.
5.68 is not a digit, it is three digits.
Such numbers are best written - and pronounced - in scientific notation. Normally you don't need all the digits, so you can round such a number to an appropriate number of significant digits - for example, 25670000..... Then you express it in scientific notation, in this example, 2.567 x 1025. Edit: I agree entirely with the previous answer but, if you must: The 2-digit name for digits 1-2 followed by "septillion", the 3-digit name for digits 3-5 followed by "sextillion", the 3-digit name for digits 6-8 followed by "quintillion", the 3-digit name for digits 9-11 followed by "quadrillion", the 3-digit name for digits 12-14 followed by "trillion", the 3-digit name for digits 15-17 followed by "billion", the 3-digit name for digits 18-20 followed by "million", the 3-digit name for digits 21-23 followed by "thousand", and the 3-digit name for digits 24-26.
The first digit can be 0 through 9, ten possibilities. Having selected the first digit, you have 9 digits to pick from the second digit. Having selected the second digit, you have 8 digits to pick from the third digit. Hence total possibilities = 10 x 9 x 8 = 720
3 and 6
The units digit of a two digit number exceeds twice the tens digit by 1. Find the number if the sum of its digits is 10.
There isn't one. The only two digit numbers whose sum of digits is 12 are: 39, 48, 57, 66. (I didn't include 75, 84, or 93 since interchanging their digits and subtracting from the original number will be a negative result.) None of the four remaining numbers will exceed the original by 25. 66 won't work since the difference will be zero. Using 39, the new number (93) will exceed the original by 54; using 48 the difference will be 36; and using 57 the difference will be 18
-- "The sum of a two-digit number" is unclear. I took it to mean"The sum of the digits of a two-digit number."-- "... the product ?" is unclear. Are you looking for the product of the two digits,or the product of the forward and backward numbers ?-- It's not possible to write a number whose two digits sum to 12 and whosereverse exceeds it by 25. The tens digit would have to be 4.611... and the unitsdigit would have to be 7.388... .Then(4.611...) + (7.388...) = 12(46.111...) + (7.388...) = 53.5(73.888...) + (4.611...) = 78.5Difference = 25So, the number can't be written, but ...The product of its two digits is 34.071 (rounded)The product of the forward and reverse numbers is 4,199.75 (rounded)
There are the digits 1 through 9 for the first digit. Then, we have 0 through 9 for the second digit - excluding the first digit. For the third digit, we have 0 through 9 excluding the two previous digits
Not necessarily. Consider 444. The digits are not different. The first and second digits are not multiples of 3 The first digit is not greater than the second digit. In spite of all that, 444 is a 3-digit number
The places are always the same no matter what the digits are. The value is obtained by multiplying the place times the digit. Starting from the right, the places in an 8-digit number are ones, tens, hundreds, thousands, ten thousands, hundred thousands, millions and ten millions.
Since there are only five different digits, a 6-digit number can only be generated if a digit can be repeated. If digits can be repeated, the smallest 6-digit number is 111111.
The two digit numbers in which the tens digit is five greater than the units digit are:5061728394The number we are looking for is ten times the sum of its digits, and so must be a multiple of 10. The only one of the above numbers which fits this is 50, as 5 is five greater than 0, and 50 = 10 x (5+0).
987654321 is the highest nine-digit number with no repeated digits.
The largest ten digit number with no repeated digits is '9876543210'.
Assuming that 2356 is a different number to 2365, then: 1st digit can be one of four digits (2356) For each of these 4 first digits, there are 3 of those digits, plus the zero, meaning 4 possible digits for the 2nd digit For each of those first two digits, there is a choice of 3 digits for the 3rd digit For each of those first 3 digits, there is a choice of 2 digits for the 4tj digit. Thus there are 4 x 4 x 3 x 2 = 96 different possible 4 digit numbers that do not stat with 0 FM the digits 02356.