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Online Quiz (Worksheet A B C D)

Questions Per Quiz = 2 4 6 8 10

Grade 7 - Mathematics
4.39 Solving Problems Using Formula for a2-b2

Example: Find the value of 49*51 using formula.

Solution: We can write 49*51 = (50-1)(50+1)
This is the form of (a-b)(a+b) = a2-b2
= 502-12
= 2500-1
= 2499


Directions: Solve the following problems using formula.
Q 1: Find the value of 109*111 using formula.
1299
12909
12099

Q 2: Find the value of 32*28 using formula.
996
896
796

Q 3: Find the value of 102*98 using formula.
9976
9986
9996

Q 4: Find the value of 62*58 using formula.
3596
4596
3956

Q 5: Find the value of 501*499 using formula.
269999
24999
249999

Q 6: Find the value of 22*18 using formula.
296
396
496

Question 7: This question is available to subscribers only!

Question 8: This question is available to subscribers only!


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