# singapore math

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.

1. 👍
2. 👎
3. 👁
1. 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?

1. 👍
2. 👎
👤
Ms. Sue
2. 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

1. 👍
2. 👎
3. 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 ?

1. 👍
2. 👎

## Similar Questions

1. ### Math

A fertilizer covers 5/8 square foot in 1/4 hour. i don't understand how to work out this math problem. By the way i'm in 6th grade but technically doing advanced math so i'm doing 7th grade math. I don't know how to do this

2. ### 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?

3. ### maths.

1) the 1st digit of the square of the second digit 2) the sum of the 2nd and the 3rd digit is 4 3) if the 4th digit is equal to 2nd digit plus 1 4) if the 3rd and the 5th digit are 15 5) the sum of all the digit is 30 i.e when you

4. ### 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

1. ### Math

The average 3rd grade student can read 60 words I 5 minutes. What is the average reading per rate? Write an expressionto represent the problem. Solve the problem

2. ### Oliver Springs

Please help,Math,Problem;John and George together raked 7/8 of the yard. John raked 3/4 of that amount. What part of the yard did John rake?

3. ### Mathematics

What is true of the number 55,555 A. Each digit has value less than the value of the digit time it's right and greater than the value of the digit itself. B. Each digit has a value 10 times the value of the digit to it's right and

4. ### ms.sue 5 grade math

1-Becky made 4 quarts of chicken noodle soup in a big pot, then served -cup bowls of soup to 6 people. How much soup is left in the pot? (1 qt = 4 c) A. none B. 1 qt 3 c C. 1 qt 1 c D. 3 c my son put answer (B) 2- A bedroom has

A teacher asks each student to pick a four or five digit password using the numbers 0 to 9. If repetition is not allowed, how many different passwords are possible? 4 digits 1st :10 2nd : 9 3rd : 8 4th : 7 4 digit password=

2. ### Math

I am a four digit number, I am between 2,000 and 3,000 the digit in the ones place is four times as much as the digit in the thousands place. Only one of the digits are the same. The digit in the tens place is one more than the