There are computer applications that do not require high (computational) accuracy and precision, or work with information that already contains uncertainty. Think of applications like neural networks, signal processing, and localisation and mapping for which an approximate result is sufficient to meet both the requirements and design goals in the computer architecture.
Design goals can be traded, such as performance, power, and energy efficiency. Techniques available for approximate computing include quantisation, rounding, truncation, and reduction of the number of bits.
Approximate computing is also achieved at the software level with dedicated algorithms, and at the hardware level by using approximate hardware, or via a combination of both. Therefore, approximate computing is gaining more traction, leading to trade-offs in accuracy in exchange for other improvements in computational objectives.