5678 x 5678 = 32239684
56.78
210.2963
5678 is only one 4-digit number. If you're willing to move the digits around to different positions, you can make 23 more.
6587
23
5678 x 5678 = 32239684
1000 milliliters= 1 liter. 5678•1000=5,678,000
56.78
5678*1 = 5678
72% of 5678 = 5678/100 x 72 = 4088.16
-5674
5678 + 69022 = 74700
42+5678 = 5720
5678 + 7467 = 13,145
5678 + 2987 = 8,665
sqrt(5678) = 75.35 approx.