Every asterisk in the equation
2 * 0 * 1 * 5 * 2 * 0 * 1 * 5 * 2 * 0 * 1 * 5 = 0
is to be replaced with either + or − so that the equation is correct. What is the smallest number of asterisks that can be replaced with +?
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Grey Kangaroo 2015 (2015)
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