Bella is more comfortable working with integers than with positive and negative decimal numbers. This is her way of understanding -4.3 + 2.5
a)Use Bella's method to determine 6.1 + (-3.9).
Okay, so for this one you have to put the decimal into fraction form. For that you have to multiply 6.1 x 10 which equals 61. Then you divide 61 by 10, so that it looks like this: 61/10. After that you multiply -3.9 x 10 which equals -39. Then you divide -39 by 10, so that it looks like this: -39/10. After that you add the two together (use a number line if that helps). The answer should be 22 tenths. Finally you convert 22 tenths back into 2.2 (shown above).
b)How could you modify Bella's method to determine 1.25 -3.46?
Well, to make this one work, you should probably use hundredths instead of tenths. Let me explain.
1.25 in words is one and twenty-five hundredths. That is why you use hundredths. It's the same for 3.46, that one is three and forty-six hundredths.
I hope that you can understand my scribe. I also hope that you enjoyed reading it! If I made no sense, PLEASE COMMENT AND TELL ME THAT :]