word problems
DESCRIPTION
Word Problems. With INTEGERS!. How to find “change”. A “change” in something can be either positive or negative so you need to be careful when you have negative numbers. To find the change, you subtract (as you know). BUT, you need to subtract the “earlier” number from the “later” number. - PowerPoint PPT PresentationTRANSCRIPT
Word Problems
With INTEGERS!
A “change” in something can be either
positive or negative so you need to be careful when you have negative numbers.
To find the change, you subtract (as you know). BUT, you need to subtract the “earlier” number from the “later” number.
For example…
How to find “change”
You have 350 RMB now and you had 200 RMB
yesterday. What was the change in the amount of money you have?
(latest) 350 minus (earliest) 200 = + 150 RMB You have 200 RMB now and you had 350 RMB
yesterday. What was the change in the amount of money you have?
(latest) 200 minus (earliest) 350 = - 150 RMB (you “lost” money)
Finding change…
A submarine was situated
800 feet below sea level. If it ascends 250 feet, what is its
new position?
Write a math expression to solve the problem.
- 800 + 250= - 550
The new position is – 550 ft.
Answer
Mount Everest, the highest
elevation in Asia, is 29,028 feet above sea level. The Dead Sea, the
lowest elevation, is 1,312 feet below sea level. What is the difference between these two elevations?
Write a SUBTRACTION sentence to solve this
problem!
29,028 – (-1,312)= 29,028 + 1,312= 30,340
The difference in the elevations is 30,340 ft.
Answer
In Buffalo, New York, the
temperature was -14 F in the morning. If the temperature
dropped 7 F, what is the temperature now?
Write a SUBTRACTION sentence to solve this
problem!
- 14 – 7= - 21
The temperature is now – 21 degrees fahrenheit.
Answer
Alicia had $837 in her bank account. She used her debit card to buy $750 worth of
clothes. Then she withdrew $580. What is in her
account?
Write a math expression to show your work.
837 – 750 - 580= 87 – 580= - 493
Alicia’s account was overdrawn by $493. (She
was in debt by this amount.)
Answer
In the Sahara desert one day
it was 136 F. In the Gobi desert a temperature of – 50 F was recorded. What is the
difference between these two temperatures?
Write a SUBTRACTION sentence to solve this
problem!
136 – (– 50)= 186
The difference between the two temperatures is 186
degrees F.
Answer
Mercury is a metal that is a liquid at room temperature. Its melting point
is – 39 C. The freezing point of mercury is – 114 C. How much warmer is the melting point of
mercury than the freezing point of mercury?
Write a SUBTRACTION sentence to solve this
problem!
- 39 – (-114)= - 39 + 114= 75
The melting point is 75 degrees warmer than the
freezing point.
Answer
(partner #1)
Explain to your partner WHY a negative times a negative is a positive.
Communicate!
(partner #2)
Explain to your partner WHEN a negative plus a
positive is negative.