Let's say we already did the work and found the result of 48*19. That result is 912.
When it comes to multiplying 0.048 and 1.9, we're going to need to do two things to transform those numbers into 48 and 19.
Move the decimal point of 0.048 exactly three spaces to the right. This is the same as multiplying by 1000. So 1000*0.048 = 48
Move the decimal point of 1.9 exactly one space to the right. This is the same as multiplying by 10. So 10*1.9 = 19
Overall, we've multiplied by 1000*10 = 10,000. This means 48*19 = 912 is 10,000 times larger compared to the result of 0.048*1.9
To fix this, we need to divide by 10,000 to get 912/(10,000) = 0.0912
Dividing by 10,000 is the same as moving the decimal point to the left four spaces. Note how 10,000 = 10^4.
I recommend using your calculator to see that 0.048*1.9 = 0.0912 which matches with the previous result we got.
