Well 4 copies of one tenth will equal 4 tenths. so when u simplify 4 over ten (4/10 )and divide the top and bottom by the common factor which is 2 then you will get 2 fifths because 4 divided by 2 is 2 and 10 divided by 2 is 5.
The arrows should start at zero because then the expression wouldn't be true. She should have made 5 groups if she had started at zero.
