Respuesta :

OK  - convert  the 2 numbers  to  one significant figure:-

102.3  = 100
4.7 = 5

So the estimate is 100/5  = 20 answer
Pickletoepi
The answer would be 20.

102.3 can be rounded down to 100 and 4.7 can be rounded up to 5. 100 divides by 5 is 20.

The trick is to find the 2 closest numbers that you can do mental math with.