Table of Contents
How many 3-digit numbers are there with no digit being repeated?
Answer: There are 648 numbers that are 3 digits numbers such that none of the digits are repeated.
When the digits of a three-digit number are reversed?
Remark: The difference of a 3-digit number and the number formed by reversing the digits is exactly divisible by 99 and the quotient so obtained is either the difference between the hundredth digit and the ones digit of the original 3-digit number or 0.
How many 3 digit numbers are there which are even and have no repeated digits use 0 9?
Hence the total number of three digit even numbers that can be formed from 0–9 without repetition = 72+256 = 328.
How many 3 digit numbers are there each digit is different?
Thus there are 60, 3 digit numbers, with distinct digits, with each of the digits odd.
What is reversing the digit?
Reversible numbers, or more specifically pairs of reversible numbers, are whole numbers in which the digits of one number are the reverse of the digits in another number, for example, 2847 and 7482 form a reversible pair.
What does it mean when digits are reversed?
What is reversing its digits?
Reversing the digits means that we have to alter the position of the digits such as if xyz is the original number where z is at the ones place, y is at the tens place and z is at the hundred place then, the number obtained by reversing the orders of the digits is zyx.
Can the first and last digits of the same number be different?
Reverse the digits and you get the same number. Subtract these and you get zero. Add the digits of zero, and you get…zero! So, maybe you should rephrase your instructions to say that the digits have to be different, or that the first and last digits can’t be the same.
What is the sum of reversed 2-digit numbers?
27 + 72 = 99. The sum of the digits in the 2-digit number determines the sum of the reversed numbers in the following way: If the sum is 6 the answer is 66 (24 + 42 = 66; 15 + 51 = 66 etc) If the sum is 8 then the sum of the reversed numbers is 88.
How do you introduce a reversed 2 digit problem?
Introduce the problem – you could do this by writing 2 reversed 2-digit numbers eg 14 and 41. Ask the students what they can tell you about the 2 numbers. If they identify that the digits have swapped places then introduce the problem.
How do you find the difference between two two digit numbers?
There is another neat trick, however: simply treat the first and last digits as though they formed a two digit number. First, find the difference using the equation for a two digit number, that is, and then place a nine between the two digits (assume a leading zero if necessary).