what is the numeral for two million, five and three hundred fifty-one thousandths

2,000,005.351

so when u have a question and it end with hundreths or thouands does that mean you use a decimal

Yes. All of these come after a decimal point:

tenths
hundredths
thousandths
ten-thousandths
hundred thousandths

If the suffix is -ths, the number represents a fraction of 1 and follows the decimal point.

http://www.mathsisfun.com/decimals.html

To find the numeral for two million, five and three hundred fifty-one thousandths, we can break it down into three parts: the whole number part (2 million), the decimal part (five and), and the fractional part (three hundred fifty-one thousandths).

1. Whole Number Part: The whole number "two million" can be written as 2,000,000. It consists of the digit 2 followed by six zeros.

2. Decimal Part: The decimal part "five and" indicates that there will be a decimal point after the whole number part. The digit immediately after the decimal point is 5, which indicates "five-tenths."

3. Fractional Part: The fractional part "three hundred fifty-one thousandths" indicates the number after the decimal point. It can be written as 0.351, where the digit 3 is in the "hundredths" place, 5 is in the "tenths" place, and 1 is in the "thousandths" place.

Now, combining all three parts, the numeral for two million, five and three hundred fifty-one thousandths is:
2,000,000 + 0.5 + 0.351 = 2,000,000.851