Let n be a natural number, then the odd number is expressed as______ , even numbers expressed as______ The number divisible by 5 is______ The number of 3 divided by 4 is______ .

Let n be a natural number, then the odd number is expressed as______ , even numbers expressed as______ The number divisible by 5 is______ The number of 3 divided by 4 is______ .

∵ even numbers must contain the factor of 2, ∵ even numbers can be expressed as 2n, ∵ odd numbers are 2n + 1 or 2N-1; similarly, the number that can be divided by 5 is 5N, and the number of 3 divided by 4 should be a multiple of 4, plus 3, which is 4N + 3; so the answer is 2n + 1 or 2N-1; 2n; 5N; 4N + 3