Today at work I was helping one of the kids (4th grader) with her homework. One thing that she had to do was a worksheet on decimals. One side had long rectangles broken up into 10 smaller rectangles and for each she needed to write the decimal of the shaded area. So, for example, if there were 5 little rectangles colored-in, the decimal would be 0.5. Some of the examples had one or more full rectangles (all 10 sections) colored-in and then one with only a few of the rectangles colored in. For example, two full rectangles colored-in and one with only two sections colored in would be 2.2. With these, she was having a VERY hard time understanding where the decimal point was supposed to go. I decided to explain it to her as tens and ones and that the tens place was on the left of the decimal point and the ones place was on the right. After doing that, she got them all right. Then, we got to the back of the page.... The back was all blocks of 100 little squares and she needed to write the decimal for the shaded area. She was counting the squares colored in and figured the # out fine, but again was having a hard time figuring out where to put the decimal. I just told her that for all of those the tens and ones places were both going to be to the right of the decimal. Then, she was fine. I'm not sure if I've explained this well enough for all of you to understand, but if you do understand what I'm talking about (haha!) could you give me any other suggestions of how I could have explained this to her?

Decimals are hard in fourth grade! I stress place value and the correct name of the place - for example, the place immediately to the right of the decimal point is tenths, and kids have a hard time because there isn't anything to do with ones like the place to the left of the decimal point. If the whole grid is shaded, it is a whole and will go to the left of the decimal point. I relate decimals to money a lot, and to fractions.

She is in the GATE program (gifted and talented education) and honestly, I don't think she's ready for half of the things she's doing in class...so that's what's causing most of the problem. I student taught in fourth grade, but in May when I left they were really just beginning fractions and didn't come close to touching decimals, so I really wasn't sure of how to explain it to her. Thanks for the advice.

Well, the hundreds block (usually called a flat) is easy to explain. Remember, that fractions mean 'out of all'. Remind her that the denominator tells what number 'all' is, and the numerator tells what amount of the whole is shaded in. Therefore, the number of rectangles shaded over one hundred is the fraction. She should be able to say the word form of decimals. If 40 are shaded in out of one hundred, she would say the fraction 40/100 (out loud). Tell her to write 40 one hundredths in decimal form. She should know her place value and be able to write 40 one hundredths as .40. It is important not to just say the decimal goes in a certain place. It must be related to place value - and to the fraction.