JAMB COMPUTER BASED TEST

Mathematics ⇒ Multiply numbers that are close to 50 with easeViews: 3265

Multiply numbers that are close to 50 with ease

#Examples
>>> 48 * 46

#Step 1: Subtract 50 from both of them
>>> 48 - 50 = -2
>>> 46 - 50 = -4

#Step 2: Cross add the result to the numbers
>>> 48 - 4 = 44
>>> 46 - 2 = 44

#Step 3: Add two zeros to one of them and divide the result by two
>>> 4400 / 2 = 2200

#Step 4 (final): Multiply the results in #step 1 together and add it to the result in #step 3
>>> (-2 * -4) = 8
>>> 2200 + 8 = 2208 (Answer)

Pretty cool isn't it?
Let take another example

#Multiply 42 * 57
#Step 1: Subtract 50 from both of them
>>> 42 - 50 = -8
>>> 57 - 50 = +7

#Step 2: Cross add the result to the numbers
>>> 42 + 7 = 49
>>> 57 - 8 = 49

#Step 3: Add two zeros to one of them and divide the result by two
>>> 4900 / 2 = 2450

#Step 4 (final): Multiply the results in #step 1 together and add it to the result in #step 3
>>> (-8 * +7) = -56
>>> 2450 + (-56) = 2450 - 56
>>> 2394 (Answer)

Try this and leave your answer as a comment below
>>> 48 * 52

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Started by: Prodigy on Feb 26, 2015

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