How do you write 2.15 1/2 in expanded form. Our topic is transforming fractions in decimal form... but what is the fraction 1/2 doing there?

well, 15 1/2 = 15.5

So I'd guess 2.155

but that's certainly an unusual way to express a value.

In fact, I'd guess it's a typo. I've never seen a mixture of decimal and fraction like that.

It is a typo

To write 2.15 1/2 in expanded form, we first need to understand what the fraction 1/2 is doing there. In this case, the fraction 1/2 is representing the decimal 0.5. So, 2.15 1/2 can be written as 2.15 + 0.5.

To write it in its expanded form, we'll convert the decimal part of 2.15 to fractional form. Here's how you can do it:

1. First, determine the place value of each digit after the decimal point. In 2.15, the digit 1 is in the tenths place, and the digit 5 is in the hundredths place.

2. Convert each digit to its fractional equivalent. Since 1 is in the tenths place, it can be written as 1/10. Similarly, since 5 is in the hundredths place, it can be written as 5/100.

3. Add these fractional equivalents to the whole number part. 2.15 = 2 + 1/10 + 5/100.

4. Simplify the fraction if possible. In this case, it can be simplified as follows: 1/10 = 10/100, so 2 + 1/10 + 5/100 becomes 2 + 10/100 + 5/100.

5. Combine the fractions by finding a common denominator. In this case, both fractions have the same denominator (100), so you can add them directly: 2 + 10/100 + 5/100 = 2 + (10 + 5)/100.

6. Simplify further if required. In this case, 10 + 5 = 15, so the final expanded form is: 2 + 15/100.

Therefore, the expanded form of 2.15 1/2 is 2 + 15/100.