Math: Grade 7

1. Katy is very interested in cryogenics (the study of
very low temperatures). With the help of her
science teacher she is doing an experiment on the
effect of low temperatures on bacteria. She cools
one sample of bacteria to a temperature of -51
degrees Celsius and another to -76 degrees
Celsius. What was the temperature difference in
the two experiments?
1)

2. Answer:
25
• How do you get the answer?
-51 – (-76)
Keep – change – opposite
-51 + 76 = 25

3. On Tuesday the mailman
delivers 3 checks (money for
you!) for $5 each and 2 bills
(money you owe!) for $2 each.
If you had a starting balance of
$25, what is the ending
balance?
2)

4. Answer is $36
How do you get this?
25 +5 + 5 + 5 – 2 -2

5. An elevator is on the twentieth
floor. It goes down 11 floors and
then up 5 floors. What floor is the
elevator on now?
3)

6. Answer is 14.
20 – 11 + 5

7. Joe is playing a game with a regular die.
If the number that turns up is even, he
will gain 5 times the number that comes
up. If it is odd, he will lose 10 times the
number that comes up. He tosses a 3.
Express the results as an integer.
4)

8. Answer: -30
How do you get this?
-10 x 3 = -30

9. It will be – 12º tonight. The
weatherman predicts it will be
25º warmer by noon tomorrow.
What will the temperature be by
noon tomorrow?
5)

10. Answer:
13°
Equation is:
-12 + 25 = 13

11. A sprinkler was -8 feet below ground
level. Mr. S has a machine that digs - 2
feet at a time. How many digs does he
need to make in order to reach the
sprinkler?
6)

12. Answer:
4 digs
Equation:
-8/-4 = 2