A binary half-adder comprising first and second oscillators, each oscillator being connected to a first input and to a second input, the second oscillator being connected to the first oscillator, wherein the first oscillator is configured to oscillate if the first input is high or the second input is high, the second oscillator is configured to oscillate if the first and the second inputs are high, and wherein the connection between the second oscillator and the first oscillator is configured to suppress oscillation of the first oscillator if the second oscillator is oscillating.