This set is listed in our original Gallaher reference book (RB.4 - published in 1944) as :
1924. 100. TRICKS & PUZZLES SERIES (titled series). Size 2 1/2" x 1 1/2". Numbered 1-100. Fronts lithographed in full colours, marginal lines and white margins. "Gallaher`s Cigarettes" incorporated in each picture. Backs printed in green with "Solution" and "Issued by Gallaher Ltd., Belfast & London." Probably printed by E. S. & A. Robinson Ltd., Bristol.
This is shortened in our World Tobacco Issues Indexes to just "TRICKS & PUZZLES SERIES. Sm. Back in green. Nd. (100)
Now let us say straight off that there is a bit of a question over the date. Our RB.4 clearly says 1924, but in the 1950 London Cigarette Card Catalogue it says 1913.
And let us also say that there is another Gallaher set by this exact same name, which luckily has a black back. You can see that at https://csgb.co.uk/publications/newsletter/2022-10-15