How do you replace the battery in a canon ls-100ts calculator?

Remove the 3 screws - latches located at TAX- CI/C & 1 0 on left side .TAX switch M- & - = on right side . Lift top up LCD part , a little , Twist the two halve in opposite directions to get first latch , Push to side get the other , separate halves .

Battery AG13 / LR44 what ever . Look at battery , in center is a little tab pushing on top of Battery , when done make sure it's there . Push battery out LCD side , not over the circuit board , may need to bend tab on side of battery holder , replace battery note + & - are right , Also note little tab on top of battery holder , bend side tab back to , after installing Battery - reassemble .