1. 8-6 Digit and Value (Money)
Assignment: 8-6/1-13 odd, odd

2. Value problems (already have done many of these in (8-4)
One equation: Quantity (number of items)
Other equation: Value (Cost, weight, etc)
Digit Problems
Any two digit number can be expressed as
10x + y ( 52: 10*5 + 2 so x =5 and y = 2)
The reverse would become
10y + x (10*2 + 5 or 25)

3. That means 350 adults attended
Example 1:
There were 411 people at a play. Admission was
$1.00 for adults and 75¢ for children. The receipts
were for $ How many children attended?
Quantity: a + c = 411
Value: 1a c =
a + c = 411
( ) -1 +
-1a c =
0.25c = 15.25
c = 61
61 children attended
That means 350 adults attended

4. That’s the nickels. Now the dimes
Example 2:
Calvin paid his skate rental of $1.35 with nickels and dimes. There were 19 coins. How many of each coin did he have?
Quantity: x + y = 19
Value: x y = 1.35
-0.10x y = -1.9
( )-0.10 +
0.05x y = 1.35
-0.05x = -0.55
11 + y = 19
y = 8
There were 8 dimes
x = 11
That’s the nickels. Now the dimes

5. Substitution will work here
Example 3:
The sum of the digits of a two-digit number is 14.
If the digits are reversed, The new number is 36
greater than the original number. Find the original
number.
Substitution will work here
y =14 - x
1st: x + y =14
2nd: 10y + x = 10x +y +36
5 + y = 14
y = 9
The number is 59
10(14 - x) + x =10x x + 36
x + x = x
140 – 9x = x
90 =18x
5 = x

6. Lets use elimination this time.
Example 4:
If 27 is added to a two digit number, the result is a
number with the same digits, but in reverse order.
The sum of the digits are 11. What is the original
number?
1st: 10x + y +27 = 10y + x
2nd: x + y = 11
Lets use elimination this time.
9x - 9y = -27
( ) 9 +
9x + 9y = 99
18x = 72
x = 4
4 + y =11
y = 7
The number is 47

7. Assignment