# Erasing Equations

To erase equations, tap the "Remove" button and follow the prompts, or use the "remove" command.

The "remove" command is used to delete equations from the list of stored equations.  One equation number can be specified, or the keyword "all" can be used to delete all of the stored equations.  Evaluated variables are not affected by the remove command.

Warning:  When an equation is removed, the equations listed after it are renumbered to fill-in the gap.  Be careful to check the equation list when using more than one remove command in succession.

`e.g.    y=mx+b          Define equation #1.        m=(y-Y)/(x-X)   Define equation #2.        b=2-q           Define equation #3.        b+q=11          Define equation #4.        remove 2        Erase equation #2, "m=(y-Y)/(x-X)".        list            Inspect the new equation list.        remove 2        Erase the "new" second equation, "b=2-q".        remove all      Erase all equations.`

Removing Equations

In the course of solving problems, some previously entered or derived equations may no longer be needed.  The program provides the "remove" command to delete equations from the set of stored equations.

`> list equations (Eq. 1)                   5 (F - 32)               C = ----------                       9      (Eq. 2)         273 + C = K (Eq. 3)               y = b + m x (Eq. 4)               w = m - b (Eq. 5)           F - C = i n (Eq. 6)                   y - Y               m = -----                   x - X`

To delete any equation, supply its equation number to the "remove" command:

`> remove 2> list equations (Eq. 1)                    5 (F - 32)               C = ----------                       9      (Eq. 2)               y = b + m x (Eq. 3)               w = m - b (Eq. 4)           F - C = i n (Eq. 5)                   y - Y               m = -----                   x - X`

When an equation is removed, the equations are re-numbered to close the gap.  Be careful to check the equation list if more than one equation needs to be removed!

`> remove 1> list equations (Eq. 1)               y = b + m x (Eq. 2)               w = m - b (Eq. 3)           F - C = i n (Eq. 4)                   y - Y               m = -----                   x - X> remove 3> list equations (Eq. 1)               y = b + m x (Eq. 2)               w = m - b (Eq. 3)                   y - Y               m = -----                   x - X`

To erase all stored equations at once, use the "remove all" command:

`> remove all`

Removing an equation does not affect the equation's evaluated variables, so the results of calculations are not lost...

`> list       K = 100       C = -173       F = -279.4       x = 13       m = 2       b = -3  [locked]       y = 23       w = 5`