Search results
Results from the WOW.Com Content Network
For example, 3 5 = 3 · 3 · 3 · 3 · 3 = 243. The base 3 appears 5 times in the multiplication, because the exponent is 5. Here, 243 is the 5th power of 3, or 3 raised to the 5th power. The word "raised" is usually omitted, and sometimes "power" as well, so 3 5 can be simply read "3 to the 5th", or "3 to the 5".
[8] [9] In programming languages such as Ada, [10] Fortran, [11] Perl, [12] Python [13] and Ruby, [14] a double asterisk is used, so x 2 is written as x ** 2. The plus–minus sign , ±, is used as a shorthand notation for two expressions written as one, representing one expression with a plus sign, the other with a minus sign.
[2] [3] Thus, in the expression 1 + 2 × 3, the multiplication is performed before addition, and the expression has the value 1 + (2 × 3) = 7, and not (1 + 2) × 3 = 9. When exponents were introduced in the 16th and 17th centuries, they were given precedence over both addition and multiplication and placed as a superscript to the right of ...
20: If the change-sign button ± is pressed before the 5, it isn't interpreted as −5, and 4 × 5 is calculated. −20 : To get the right answer, ± must be pressed last, even though the minus sign isn't written last in the formula.
Subscripts are used in chemical formulas. For example, the chemical formula for glucose is C 6 H 12 O 6 (meaning that it is a molecule with 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms). The chemical formula of the water molecule, H 2 O, indicates that it contains two hydrogen atoms and one oxygen atom.
Some elementary teachers use raised minus signs before numbers to disambiguate them from the operation of subtraction. [21] The same convention is also used in some computer languages. For example, subtracting −5 from 3 might be read as "positive three take away negative 5", and be shown as 3 − − 5 becomes 3 + 5 = 8, which can be read as:
Where a power of ten has different names in the two conventions, the long scale name is shown in parentheses. The positive 10 power related to a short scale name can be determined based on its Latin name-prefix using the following formula: 10 [(prefix-number + 1) × 3] Examples: billion = 10 [(2 + 1) × 3] = 10 9; octillion = 10 [(8 + 1) × 3 ...
This is also referred to as a "one fold increase". Similarly, a change from 30 to 15 is referred to as a "0.5-fold decrease". Fold change is often used when analysing multiple measurements of a biological system taken at different times as the change described by the ratio between the time points is easier to interpret than the difference.