singapore math

posted by .

My 3rd grade son get this math problem.
It states that John thinks of a 3-digit number. What is his number? Use the clues below to find John's number.

Every digit is different.
The sum of all thedigits is 19.
The difference between the hundreds digit and the ones digit is 6.
The tens digit is the greatest digit.
The number is greater than 500.

Please Help.

  • singapore math -

    Use trial and error.


    The hundreds digit is 6, 7, 8, or 9

    The ones digit is 0, 1, 2, or 3

    The tens digit is 7, 8, or 9

    Can you figure this out now?

  • singapore math -

    if hundreds-ones=6, then we have

    9x3
    8x2
    7x1
    6x0

    Since the digits add to 19, 7x1 and 6x0 are out, leaving

    9x3 or 8x2

    If tens is greatest, 9x3 is out, so we must have

    892

    This must be the number, since the only other choice would be 298, where the difference between hundreds and ones is still 6, but in the other direction

  • singapore math -

    x y z
    x + y + z = 19
    |x-z| = 6
    x >/= 5
    y >/= 6
    so x+y >/= 11
    so z </= 8 to get 19 sum

    z < 6 because y is biggest
    choices
    x 5 6 7 8 9
    y 6 7 8 9
    z 0 1 2 3 4 5 6 7 8
    but x and z differ by 6 so
    x 5 6 7 8 9
    y 6 7 8 9
    z 0 1 2 3
    now what adds to 19 there with y biggest?
    none until y = 9
    so x 9 z
    but x and z differ by six
    8 and 2 differ by six
    8 9 2 ?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    The number uses every number 0-9 the numbers are used only once the fourth digit is 4 the first digit in the billions place is 3 the 5 is next to the last digit the sixth digit is 7 the digit after 3 is 9 the digit before 5 is 2the …
  2. word problem

    the different between the digit of a two digit number is 1, the number it self is 1 more than 5 times the sum of the digits, if the unit digit is greater than the tens digit, find the number.
  3. word problem

    the different between the digit of a two digit number is 1, the number it self is 1 more than 5 times the sum of its digits, if the unit digit is greater than the tens digit, find the number.
  4. maths

    Find the sum of all 3-digit positive numbers N that satisfy the condition that the digit sum of N is 3 times the digit sum of N+3. Details and assumptions The digit sum of a number is the sum of all its digits. For example, 1123 has …
  5. Math Decimals

    Jason has 4 tiles. Each tile has a number printed on it. The numbers are 2,3,6, and 8. A decimal number is formed using the tiles and the clues. Be a math detective and find the number. Clues: digit in tens place is the greatest number. …
  6. Math

    John chooses a 5-digit positive integer and deletes one of its digits to make a 4-digit number. The sum of this 4-digit number and the original 5-digit number is 52713. What is the sum of the digits of the original 5-digit number?
  7. Maths

    in a game you have to guess what a number is through some clues the clues you are given are the hundreds digit is twice as large as the thousands digit the ones digit is the largest the sum of the digits is 14 the tens digit is two …
  8. math

    a number with missing digits is given below.study the given clues and find out this number: 6_ _ _6 clues: a). the tens digit is 2 more than thee ones digit. b).the hundreds digit is 5 less than the tens digit. c).the thousands digit …
  9. math

    Neelesh is fond of playing number games. Once when his friends were present he challenged them. He said that he has thought of a five-digit number and anyone who guesses it correctly can use his cycle for a full day. ‘To help you,’ …
  10. Math

    John is thinking of a number in the hundred thousands the first digit is equal to the number of digits in the number. the number has twenty tens and twice as many thousands. the number of ones is an odd number that is less than five …

More Similar Questions