Daily one shortcut

                                              48*54

You've selected the correct notional base ie 50 but the actual base is 10. here r the steps

1) 48 -> -2 & 54 ->+4 (subtracting from base)

2) 52 // -8 (either 48 + 4 or 54 - 2 // -2 x +8)

3) since 50(notional base is 5 times actual base of 10, multiply 52 by 5 260 // -8

4) multiply left hand side by 10 (base) and add it to the right hand side

2600 + (-8) = 2592