9514 1404 393
Answer:
not possible
Step-by-step explanation:
Among the first 20 natural numbers, the numbers 10, 11, 13, 14, 18, 19 are not possible to make using four 4s and the four basic arithmetic operations.
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Below are listed the numbers that can be made and one possible way to do it.
{1, ((4*4)/4)/4}, {2, (4/(4+4))*4}, {3, ((4*4)-4)/4}, {4, ((4-4)*4)+4},
{5, ((4*4)+4)/4}, {6, ((4+4)/4)+4}, {7, (4-(4/4))+4}, {8, ((4*4)-4)-4},
{9, ((4/4)+4)+4}, {12, (4-(4/4))*4}, {15, (4*4)-(4/4)}, {16, ((4*4)*4)/4},
{17, (4*4)+(4/4)}, {20, ((4/4)+4)*4}
