Write the number 31 in tens and ones. 2 tens _ones its has 2 tens and _ ones

If you can solve all of these i will give ! - 4% of 190 - 4% of 162.5 - 4% of 140 - a 4% increase from 155.1 - a 4% increase from 159.8

Could somebody me with this radical simplification?

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square