1. With INTEGERS!

2.   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”

3.   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…

4.  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.

5.  - 800 + 250 = - 550 The new position is – 550 ft. Answer

6.  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!

7.  29,028 – (-1,312) = 29,028 + 1,312 = 30,340 The difference in the elevations is 30,340 ft. Answer

8.  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!

9.  - 14 – 7 = - 21 The temperature is now – 21 degrees fahrenheit. Answer

10.  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.

11.  837 – 750 - 580 = 87 – 580 = - 493 Alicia’s account was overdrawn by $493. (She was in debt by this amount.) Answer

12.  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!

13.  136 – (– 50) = 186 The difference between the two temperatures is 186 degrees F. Answer

14.  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!

15.  - 39 – (-114) = - 39 + 114 = 75 The melting point is 75 degrees warmer than the freezing point. Answer

16.  (partner #1) Explain to your partner WHY a negative times a negative is a positive. Communicate!

17.  (partner #2) Explain to your partner WHEN a negative plus a positive is negative.