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We are required to write a JavaScript function add() that takes in two numbers m and n. The function should, without using the four basic arithmetic operations add the two numbers taken as input and return the sum.

The code for this will be −

const m = 67, n = 33; const add = (x, y) => { while(y !== 0){ let carry = x & y; x = x ^ y; y = carry << 1; }; return x; }; console.log(add(m, n));

Sum of two bits can be obtained by performing XOR (^) of the two bits. And the carry bit can be obtained by performing AND (&) of two bits.

We have here used an extended version of the Half Adder logic that can be used to add 2 single bits to add two integers. If x and y don’t have set bits at the same position(s), then bitwise XOR (^) of x and y gives the sum of x and y.

To incorporate common set bits also, bitwise AND (&) is used. Bitwise AND of x and y gives all carry bits. We have calculated (x & y) << 1 and added it to x ^ y to get the required result.

And the output in the console will be −

100

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