## Wednesday, 21 January 2015

### Weekend Food for Thought: Pondering over Primes 01

A number's prime factorisation is
23 X 32 X 52
Is the number even or odd? Explain your reasoning.
Name four other factors of this number, other than 2, 3 and 5.

Remember to include your Group Number at the end of the comment.
Complete by 18 January 2015.

1. The number is even is 5 to the power of 2 is 10 and any natural number times 10 will be an even number

1. Hsien Kit
Yes... the number is even.
However, the reasoning is incomplete.

2. 5^2 is 10? it should be 25

3. @Marcus: Please elaborate to Hsien Kit why 5^2 should be 25.

2. even. 5 to the power of 2 is 10 so, the number multiply by ten, it will be even

1. any number multiply by 10* just changing

2. @Ming En
"5 to the power of 2" is same as "5 X 5".
So, what would you get?

3. @Zi Bo
What do you mean by "multiply by 10*"?

3. Even. Any number multiplied by an even number is always even

Group 2

1. @Kevin

You are very close to the good answer.
How do you improve your explanation, "Any number multiplied by an even number is always even"?

4. As a number in the equation (2) is an even number and any number multiplied by an even number is an even number, the result is an even number.

Four other factors of the number are 4, 9, 25 and 8.

Group 2.

1. @Tjin Yao

Note that it's an arithmetic expression (equation 'looks' slightly different).
The 'even number' you mentioned - are you referring to Base or Power?
In addition, if you are listing the factors, there are more factors than what you have entered. Are you able to list down the missing ones?

PS: You can reply to this comment.

2. I am referring to the base number.

I'm not really sure how to find all the factors, but I guess 6, 10 and 15 are factors because 2*3, 2*5 and 5*3.

5. Even. Since only even numbers can be divided by 2, thus any number times 2 or to the power of 2 will always be even

1. @Marcus: "any number times 2" and "any number to the power of 2" mean different things.

Does "any number to the power of 2" always give us an even number?
Test that out with several numbers.