Answer:
the last digit is 5
Step-by-step explanation:
an adult has 4.94 x 10^13 cells = 49,400,000,000,000
49,400,000,000,000 - 26,000,000,000 = 49,374,000,000,000
scientific notation form : 4.9374 x 10^13
22
There is really no explanation to doing this, you just have to put them side by side and descend both numbers by how much they ascend each time by 1 multiple.