Page 46 - Math Smart - 7

Spotlight m) -8 - (-4) - (+4) = n) -16-(17) =
o) 8-(-22) = p) _ii_(_36) =
The additive inverse is
q) 0-(+9) = r) -4-(+7)-(+4) =
the number you must
s) 3 + 2-(+5) = t) -6 + 5-(-2) =
either add to, or subtract
from, another number to Find the value of each of the following,
get an answer of zero.
a) 1 + 5 + 3 = b) 3 + 12 + 8 =
A number and its
c) -3-2-1 = d) -13-7 + 2 =
additive inverse are
e) -8 + 2 - 5 = f) -11+6 + 10 =
always the same distance
from zero on a number g) 7-5 + 3- 9= h) -7 + 7 - 2 =
line. i) -3 + 5 + 3= j) 1+6-1-6=

<1*1 I I ! I I I I i"!*" O Kim is interested in cryogenics, which is the science of very low
-5-4-3-2-1 0 1 2 3 4 5
temperatures. He is doing an experiment on how low temperatures
The integers -5 and 5 are affect the growth of bacteria. He cools one sample of bacteria to
the same distance from a temperature of -58''C and another sample to -82°C. What is the
zero. temperature difference in the two experiments?
The integer-5 is the
We have learnt to calculate 13 + (-27).
additive inverse of 5.
a) Explain in words or diagrams how you would work this out.
The integer 5 is the
b) Describe a situation where this calculation would be used.
additive inverse of -5.

Speed Challenge

Let's do a timed practice for adding and subtracting integers. Your teacher
will set and stop the timer on a stopwatch. Answer the questions as fast and as
accurately as you can.
Ready, steady, go!

Simplify the following.

1. (-3) +(-20)= . 11. (-6) + (-3) =
2. (-5) +(-6)= . 12. (+15) +(-3) =
3. (+5) +(-12)= . 13. -8 +(-5) =
=
4. (-10)+ (+18) = 14. -l4 + (^)
5. -4 + (-1) = 15. 4 + 2 + (-3)+(-1) =
+
6. -7 +(-2) = 16. ^ 3 + (-2) + 6 =
7. -4 + (-7) + 3 = 17. -4-6 + 3 =
8. -A + (+5) + 1 = 18. 9 + 2-3-6 =
9. (-8) +(-2)= , 19. -1-15 + 4+7 + 11 =
10. (-3) + (-8) = 20. -14 + 23-12 + 5 =

Exchange books with your classmate for peer marking.
Write the score out of 20 at the top of the challenge. What went right for
you? Discuss your answers with your partner. Where did you go wrong?

Integers