Computations of expressions which contain addition, subtraction, multiplication and division

Computations of expressions which contain addition and subtraction

The expression 3 + 5 + 7 expresses the addition of 7 to 3 + 5. The expression 3 - 5 + 7 expresses the addition of 7 to 3 - 5. Like this, you can compute the expression which contains addition and subtraction in order from left to right. When there are parentheses, you compute the inside of the parentheses first. Here, you can try to do it. When clicking the button, an expression is displayed. Some parts of the expression are surrounded by the frame. Next, you click inside of a frame which surrounds the part of the expression that you want to compute, then the part becomes its result and you can compute the part. Thus you can compute the whole of the expression at last.

If the part of the expression becomes like "-2" or "-9", you can not compute such parts of the expression any more.

Computations of expressions which contain moreover the operation which changes the sign

The positive integer n becomes a negative integer -n with putting the symbol "-" before n. Similarly the symbol "-" means with putting the symbol "-" before the expression, it becomes the negative integer of the same "size" as the original expression (its result) if the original expression (its result) is positive, and it becomes the positive integer of the same "size" as the original expression (its result) if the original expression (its result) is negative.

The point that is expressed by the figure is the point of the same length from 0 as the original point and of the opposite direction as the original point.

You may enclose with parentheses like -(3 + 7), when you put "-" to an expression like 3 + 7.

Because we have no priority among the sign changing operation "-", the addition "+" and the subtraction "-", we must enclose with parentheses. The multiplication and the division are prior to the sign changing operation "-".

The expression - 3 + 6 - 4 + 5 expresses (- 3) + 6 - 4 + 5.

Computations of expressions which contain moreover the multiplication

Like 2 * 3 + 5 * 6, to compute expressions which contain the multiplication and the addition (or the subtraction), you may do earlier the multiplication, 2 * 3 + 5 * 6 = 6 + 30 = 36.

We sometimes write ab for a * b.

You can write an expression in the following.

Usage: You can make an expression simple which contains addition, subtraction, multiplication and division. When You click the inside of the frame, the part of the expression there can be made simple. An expression of the form

Integer + Integer
Integer - Integer
Integer * Integer
Integer / Integer

can be made simple. The integer is a positive integer, or a - positive integer, or 0. The division by 0 is not possible. The division can be made simple only if it is divisible.

You input the text box "Expression" and click the "set" button, then you can change the expression. You can input an expression containing addition, subtraction, multiplication, division, - (change sign) and parentheses. The number can be a positive integer or 0. Please use the operator "*" for multiplication, the operator "/" for division.