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Online Quiz (Worksheet A B C D)

Questions Per Quiz = 2 4 6 8 10

Grade 8 - Mathematics
7.20 Solving Problems Using Formula for (a+b)(a-b)

Example: Find the value of 9.2*8.8 using formula.
Solution: We can write 9.2*8.8 = (9+0.2)(9-0.2)
This is the form of (a+b)(a-b) = a2-b2
= 92-(0.2)2
= 81-0.04
=80.96
Directions: Solve the following problems. Also write at least ten examples of your own.
Q 1: Find the value of 10.1*9.9 using formula.
99.99
89.89
9.9

Q 2: Find the value of 10.01*9.99 using formula.
99.9999
99.99
99.999

Q 3: Find the value of 100.2*99.8 using formula.
999.96
99.96
9999.96

Q 4: Find the value of 49.95*50.05 using formula.
2499.975
249.9975
2499.9975

Question 5: This question is available to subscribers only!

Question 6: This question is available to subscribers only!


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