  We present the design of a quantum carry-lookahead adder using
measurement-based quantum computation. QCLA utilizes MBQC`s ability to transfer
quantum states in unit time to accelerate addition. The quantum carry-lookahead
adder (QCLA) is faster than a quantum ripple-carry adder; QCLA has logarithmic
depth while ripple adders have linear depth. QCLA is an order of magnitude
faster than a ripple-carry adder when adding registers longer than 100 qubits
but requires a cluster state that is an order of magnitude larger. Hand
optimization results in a $\approx$ 26% reduction in spatial resources for the
circuit.
