1, "Year Month Day" jingle

One, three, five, seven, eight, ten, wax, 3 1 day is always big. April, June, September, November, 30 days is never bad.

February, the most special, February and February changes. Twenty-nine leap years and twenty-eight average years.

Except the year number is even, the whole century number is marked with double zeros.

2, around children's songs

The rounding method is good, and the approximate figure can be found out by law; Take which one to look at the next one, and then compare it with five words; It is 5 big 5 forward 1, and all small 5 are discarded; The equal sign is replaced by an equal sign, which makes people understand at a glance.

3, multi-digit rewrite songs

Remove the "0" after ten thousand digits and add ten thousand characters to complete the change. Remove the "0" after one billion digits and add one billion words to correct it.