小数点以下はどこまで計算すればよいでしょうかって英語でなんて言うの？

Decimal places is the key term here. Decimal places are "rounded off" when the amount of numerals after the decimal point are limited.

Example "should I calculate 2 places after the decimal point?". "How many places after the decimal point should I calculate?".

A 'decimal place' is the position of a number digit to the right of a decimal point. For example: "Calculate to three decimal places".

You can talk in terms of 'decimal places' or in terms of 'decimal points.' They are the same thing. You may be given an instruction: "Please work to two decimal places and round up or down as necessary." To round up or down = This means the third decimal point would be ignored if 0.4 or below, or if 0.5 or above, the second decimal figure would go up by one in this case.

"How many places after the decimal points must I work out to?" This asks the teacher how many numbers after the decimal point you need. "How many places after the decimal points do I need to calculate?" This is another way of asking how many numbers you need to work out after the point.

I should calculate to how many decimal places?/I'm rounding off to how many decimal places?- A decimal numer is a fraction and not a whole number like 34.45 ml, 1.58cm A:I'm rounding off to how many decimal places. B: two decimal places for all questions.

"Within how many decimal points"? will determine just how accurate the maths question will be answered... in percentages of "a whole number" ;-D Its a complex calculation...within how many decimal points should I answer ?