Kate's model is correct because 10 times the value of 4 rods, 10(4(10)), is 400. Mel's model represents 4(1)=4, which is incorrect. Kate's model represents 4*100=400, which is correct.
Hope I answered your question!
It is true. here is how........
4-0 is rounding down
5-9 is rounding up
when rounding to the tenths place you look at the hundredths place to find the answer.