Answer:
0.00492 = 4.92×10^-3
Step-by-step explanation:
Calculators are made for the purpose of dealing with such numbers. If you like, you can write the problem in scientific notation as ...
(1.23×10^6)×(4×10^-9) = 4×1.23 × 10^(6-9) = 4.92×10^-3
The exponent of -3 means the most significant digit of the mantissa is in the 3rd decimal place to the right of the decimal point. So, in standard form, the product is ...
0.00492