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Compared to traditional long multiplication, the grid method differs in clearly breaking the multiplication and addition into two steps, and in being less dependent on place value. Whilst less efficient than the traditional method, grid multiplication is considered to be more reliable , in that children are less likely to make mistakes.
Karatsuba multiplication of az+b and cz+d (boxed), and 1234 and 567 with z=100. Magenta arrows denote multiplication, amber denotes addition, silver denotes subtraction and cyan denotes left shift. (A), (B) and (C) show recursion with z=10 to obtain intermediate values. The Karatsuba algorithm is a fast multiplication algorithm.
First multiply the quarters by 47, the result 94 is written into the first workspace. Next, multiply cwt 12*47 = (2 + 10)*47 but don't add up the partial results (94, 470) yet. Likewise multiply 23 by 47 yielding (141, 940). The quarters column is totaled and the result placed in the second workspace (a trivial move in this case).
To use REDC to compute the product of 7 and 15 modulo 17, first convert to Montgomery form and multiply as integers to get 12 as above. Then apply REDC with R = 100, N = 17, N′ = 47, and T = 12. The first step sets m to 12 ⋅ 47 mod 100 = 64. The second step sets t to (12 + 64 ⋅ 17) / 100.
In number theory, given a positive integer n and an integer a coprime to n, the multiplicative order of a modulo n is the smallest positive integer k such that (). [ 1 ] In other words, the multiplicative order of a modulo n is the order of a in the multiplicative group of the units in the ring of the integers modulo n .
Because each step, on average, halves the size of the multiplier (0 ≤ r < a, average value (a−1)/2), this would appear to require one step per bit and be spectacularly inefficient. However, each step also divides x by an ever-increasing quotient q = ⌊ m / a ⌋ , and quickly a point is reached where the argument is 0 and the recursion may ...
In any case, this algorithm will provide a way to multiply two positive integers, provided is chosen so that < +. Let n = D M {\displaystyle n=DM} be the number of bits in the signals a {\displaystyle a} and b {\displaystyle b} , where D = 2 k {\displaystyle D=2^{k}} is a power of two.
A simple arithmetic calculator was first included with Windows 1.0. [5]In Windows 3.0, a scientific mode was added, which included exponents and roots, logarithms, factorial-based functions, trigonometry (supports radian, degree and gradians angles), base conversions (2, 8, 10, 16), logic operations, statistical functions such as single variable statistics and linear regression.