Calculation is the determination of something by using mathematics. One can evaluate an expression on the Scratch Wiki using the parser function #expr. There is a 14 digit limit for rational and irrational digits; rational numbers will show up as scientific notation as it passes the 14th digit.

## Usage

To use this function, simply use the syntax {{#expr:expression}}. For example, {{#expr:2+2}} is equal to 4, but {{#expr:5/0}} will result in an error (division by zero is undefined), similar to an error produced by the template {{error}}. This function also accepts wiki variables in it; {{#expr:{{CURRENTDAY}}^2}} is equal to 4. Common supported operators include `-,+,*,/,^,`brackets and common functions include `sin( ), cos( ), tan( ), ln( ), abs( ), ceil( ), floor( ), mod( )`. Irrational numbers are also supported, such as pi and e.

## Operators Note: In logic gate functions (`not, and, or`), 0 equals false, 1 equals true. Other values always equal true.
Operators
Operator Explanation Example
`+` Adds two operands together or a unary operator {{#expr:5+5}} = 10
Five plus five is equal to ten.
{{#expr:+7}} = 7
(Positive) seven is equal to (positive) seven.
`-` Subtracts two operands or a unary operator {{#expr:10-3}} = 7
Ten minus three equals to seven.
{{#expr:+-8}} = -8
(Positive) negative eight is equal to negative eight.
`*` Multiplies two operands together {{#expr:2*9}} = 18
Two multiplied by nine equals to eighteen.
`/` Divides two operands {{#expr:35/7}} = 5
Thirty-five divided by seven is equal to five.
`^` Exponent, Multiplies the number x times {{#expr:4^3}} = 64
Four to the power of three is equal to sixty-four.
`!=` Inequality {{#expr:2!=6}} = 1
Two is unequal (True(1)) to six.
{{#expr:3+2^2!=7}} = 0
Two to the power of two (four) plus three (seven) is not unequal (False(0)) to seven.
`=` Equality {{#expr:(4-2)^2=4}} = 1
Four minus two (two) to the power of two (four) is equal (True(1)) to four.
{{#expr:9+3^2=144}} = 0
Three to the power of two (nine) plus nine (eighteen) is not equal (False(0)) to one hundred and forty-four.
`>` Greater than {{#expr:2>1}} = 1
Two is greater than (True(1)) one.
{{#expr:e>e}} = 0
The Euler number (2.71828...) is not greater than (False(0)) itself.
`>=` Greater than or equal to {{#expr:7>=7}} = 1
Seven is equal to (True(1)) seven.
{{#expr:2>=0}} = 1
Two is not greater than (False(0)) zero.
`<` Less than {{#expr:1<{{#expr:4/3}}}} = 1
One is less than (True(1)) four-thirds (1.333...).
{{#expr:abs-50<22}} = 0
The absolute value of negative fifty (fifty) is not less than (False(0)) twenty-two.
`<=` Less than or equal to {{#expr:9<=(8+({{#expr:1/3}}+{{#expr:2/3}}))}} = 1
Nine is equal to (True(1)) one third added to two thirds.
{{#expr:2<=1}} = 0
Two is not less than (False(0)) one.
`abs` Absolute value {{#expr:abs-6}} = 6
The absolute value of negative six is equal to (positive) six.
`acos` Inverse of cos function {{#expr:acos0.2}} = 1.3694384060046
The arccosine of zero and two tenths (one fifth) of a radian is about one and four tenths.
{{#expr:acos(55*pi/180)}} = 0.284040117616
The arccosine of fifty-five degrees is about zero and three tenths.
`and` Logical AND {{#expr:5 and 4}} = 1
True(5) and True(4) is equal to True(1).
{{#expr:0 and 0}} = 0
False(0) and False(0) is equal to False(0).
`asin` Inverse of sine function {{#expr:asin0.5}} = 0.5235987755983
The arcsine of zero and five tenths (one half) of a radian is about zero and five tenths (one half).
{{#expr:asin(35*pi/180)}} = 0.65715296949619
The arcsine of thirty-five degrees is about zero and seven tenths.
`atan` Inverse of tan function {{#expr:atan0.1}} = 0.099668652491162
The arctangent of zero and one tenth of a radian is about one and one tenth.
{{#expr:atan(90*pi/180)}} = 1.0038848218539
The arctangent of ninety degrees is about one.
`ceil` Raises the decimal to the next integer {{#expr:ceil-3.9}} = -3
The ceiling of negative three and nine tenths is equal to negative three.
`cos` Cosine function {{#expr:cos0.8}} = 0.69670670934717
The cosine of zero and eight tenths (four fifths) of a radian is about zero and seven tenths.
{{#expr:cos(3*pi/180)}} = 0.99862953475457
The cosine of three degrees is about one.
`div` Same as division {{#expr:6 div 2}} = 3
Six divided by two is equal to three.
`exp` Irrational number e (euler number) to x power {{#expr:exp5}} = 148.41315910258
The Euler number to the power of five is about one hundred and forty-eight.
`floor` Lowers the decimal to the next integer {{#expr:floor-6.79}} = -7
The floor of negative six and seventy-nine hundredths is equal to negative seven.
`ln` Natural logarithm {{#expr:ln(e^5)}} = 5
The (natural) logarithm for e to the power of five is five.
{{#expr:ln pi/ln10}} = 0.49714987269413
The base ten (natural) algorithm for pi is about zero and five tenths.
`mod` Modulo, remainder {{#expr:19 mod 7}} = 5
The remainder of nineteen divided by seven is five.
`not` Logical NOT {{#expr:not 4}} = 0
Not True(4) is equal to False(0).
{{#expr:not 0}} = 1
Not False(0) is equal to True(1).
`or` Logical OR {{#expr:0 or 0}} = 0
False(0) or False(0) is equal to False(0).
{{#expr:0 or 5}} = 1
False(0) or True(5) is equal to True(1).
`round` Rounds the number to the xth digit after the decimal {{#expr:1.4757027 round 3}} = 1.476
One and four million, seven hundred fifty-seven thousand, twenty-seven ten-millionths rounded to the third digit after the decimal point is equal to one and four hundred seventy-six thousandths.
{{#expr:82978 round -2}} = 83000
Eighty-two thousand, nine hundred and seventy-eight rounded to the second digit before the decimal point is equal to eighty-three thousand.
`sin` Sine function {{#expr:sin1}} = 0.8414709848079
{{#expr:sin(30*pi/180)}} = 0.5
The sine of thirty degrees is equal to zero and five tenths (one half).
`tan` Tangent function {{#expr:tan0.9}} = 1.2601582175503
The tangent of zero and nine tenths (nine tenths) of a radian is about one and three tenths.
{{#expr:tan(45*pi/180)}} = 1
The tangent of forty-five degrees is equal to one.
`trunc` 'Truncates' x into an integer without rounding {{#expr:trunc-7.8}} = -7
Truncated negative seven and eight tenths is equal to negative seven.

Therefore,

• {{#expr:(0or1)+1}} = 2
• {{#expr:0or not1}} = 0
• {{#expr:------5}} = 5
• {{#expr:not not 1}} = 1
• {{#expr:not0 or not0 and not1}} = 1
• {{#expr:pi/pi and pi*pi/pi}} = 1
• {{#expr:.}} = 0
• {{#expr:.1}} = 0.1
• {{#expr:e-6}} = -3.281718171541
• {{#expr:1e-6}} = 1.0E-6

## Errors

An error will result if:

• An operator is missing a parameter.
• {{#expr:2+}} gives Expression error: Missing operand for +.
• There is an unexpected number or operator.
• {{#expr:2 3}} gives Expression error: Unexpected number.
• {{#expr:=}} gives Expression error: Unexpected = operator.
• An unsupported word or character is used.
• {{#expr:what}} gives Expression error: Unrecognized word "what".
• {{#expr:%}} gives Expression error: Unrecognized punctuation character "%".
• A mathematical error occurs.
• {{#expr:1/0}} gives Division by zero.
• {{#expr:ln-1}} gives Invalid argument for ln: <= 0.

If a number is too large, it returns INF (positive infinity) or -INF (negative infinity).

• {{#expr:1e309}} gives INF
• {{#expr:-1e309}} gives -INF