英语翻译
1、The number of diagonals that can be drawn in a regular polygon with twenty sides（icosagon）is ( )
2、The greatest number of Mondays,which can occur in 45 consecutive days,is ( )
3、You have 3 weights:1kg,3kg,9kg as well as an equal arm balance,as shown.How many different weight objects can you weigh with these three?
4、The least natural number whose digits sum equals 100,is ( )