No, what I showed is exactly what it has in the workbook. They have a textbook, but they keep them at school, so it makes it hard for us when we are trying to help her figure something out. I explained to her what Hilmar said about the first digit, etc, and she thinks that sounds like what her teacher was talking about. I have never heard of this before. If I did it in school they called it something different. Of course when I went to school we were using rocks and sticks to do calculations...

>Is it listed anywhere in the book whether it is front-end estimation or rounding to the 1st or 2nd significant digit?
>
>
>>This is a sample problem out of a math workbook. I get that "estimating" essentially means performing calculations on rounded values, but they are mixing the places they round to in the example below. Why isn't it either 1 x 4 or 0.8 x 4.2? Not quite getting how they are doing that. I thought with rounding, you had to know the place you wanted to round to in order to have the product be valid.
>>
>>

>>Estimate Decimal Products
>>-------------------------
>>
>>Estimate 4.2 x 0.843
>>
>>  0.843 -------->   0.8
>>x   4.2 -------->  x  4
>>                   ====
>>              about 3.2
>>
>>Both factors are rounded
>>down. The actual product
>>is greater than 3.2.
>>