This was my way of solving it:
1) Find the multiples between 1 and 39.
39/3 = 13 >> There are 13 multiples of 3 from 1 to 39.
The same applies to -39 to -1 so it should have also 13 multiple between -39 and -1
And finally, you should count the 0 as a multiple.
13 + 13 + 1 = 27.
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It should also work with ranges. For example, multiples of 4 between 41 and 121:
Multiple right before the smallest >> 40 >> 40/4 = 10
Multiple right before the biggest >> 120 >> 120 / 4 = 30
30 - 10 = 20
Multiples of 4 between 41 and 121: 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120.
How many multiples of 3 are there between -40 and 40?
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mariliatgd
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We can use the formula:VJesus12 wrote:How many multiples of 3 are there between -40 and 40?
A. 13
B. 17
C. 23
D. 26
E. 27
(largest multiple of 3 - smallest multiple of 3)/3 + 1
[(39 - (-39)]/3 + 1 = 78/3 + 1 = 26 + 1 = 27
Answer: E
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