EXAMPLE: Melanie's Mother is 38 years old. She is 14 years older than 3 times Melanie's age.
How old is Melanie?
Work Backward: Start from the result and apply the operation in reverse order. (disregard the
MDAS/GMDAS rule in this strategy)
Equation: 3x + 14 = 38
✓ Check:
3 x n + 14 = 38
38-14 + 3 = n
24 + 3 =n
8 = n
3 x n + 14 = 38
3 x 8 + 14 = 38
24 + 14 = 38
38 = 38
n = 8
ACTIVITY 1
Solve for the unknown.
1. n-34 = 26
3. 2y + 4 = 32
5.0 + 13 = 28
2. d + 12 = 97
4. 5m - 8 = 42
ACTIVITY 2
Write the equation for each problem. Find the unknown.
1. Carlo has 98 customers in his newly built coffee shop. This is 4 more than twice the number
of his costumers last year. How many costumers did he have last year.
2. Brian gave 10 stamps from his collection to both Sam and Rob. Then he gave 14 stamps to Kathy
and 6 stamps to Grace. He still had 275 stamps. How many stamps were in Brian's collection to
begin with?
3. Amy and Judy sold 12 show tickets altogether. Amy sold 2 more tickets than Judy. How
many tickets did each girl sell?
4. Luisa will make loombands. She has 13 red strings and has 7 fewer yellow strings than the
red strings. How many strings does Luisa have in all.
5. Joey wants to buy a math book which cost Php 500.00. This is Php 74 more than three times
the amount he has saved. How much has he saved?
How old is Melanie?
Work Backward: Start from the result and apply the operation in reverse order. (disregard the
MDAS/GMDAS rule in this strategy)
Equation: 3x + 14 = 38
✓ Check:
3 x n + 14 = 38
38-14 + 3 = n
24 + 3 =n
8 = n
3 x n + 14 = 38
3 x 8 + 14 = 38
24 + 14 = 38
38 = 38
n = 8
ACTIVITY 1
Solve for the unknown.
1. n-34 = 26
3. 2y + 4 = 32
5.0 + 13 = 28
2. d + 12 = 97
4. 5m - 8 = 42
ACTIVITY 2
Write the equation for each problem. Find the unknown.
1. Carlo has 98 customers in his newly built coffee shop. This is 4 more than twice the number
of his costumers last year. How many costumers did he have last year.
2. Brian gave 10 stamps from his collection to both Sam and Rob. Then he gave 14 stamps to Kathy
and 6 stamps to Grace. He still had 275 stamps. How many stamps were in Brian's collection to
begin with?
3. Amy and Judy sold 12 show tickets altogether. Amy sold 2 more tickets than Judy. How
many tickets did each girl sell?
4. Luisa will make loombands. She has 13 red strings and has 7 fewer yellow strings than the
red strings. How many strings does Luisa have in all.
5. Joey wants to buy a math book which cost Php 500.00. This is Php 74 more than three times
the amount he has saved. How much has he saved?
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