You can select the range for the random words, so that you can focus on simpler or more advanced words. To set the range, click on the number above [RANDOM] [ 1 ] (after clicking on [RANDOM] first). Then enter the higher and lower bounds of the words [ 2-3 ] (e.g. 12,000 and 14,000) and click [RANDOM][ 4 ]. All future random words will be in the selected range, until/unless you change the range again. To hide the boxes [ 2-3 ], click on the number [ 1 ] again.