Ones digit of a multiplication, solving a factor
This skill involves determining a digit such that when it is multiplied by another specific digit (4 in this example), the product has a specified ones digit (2 in this example). The solution explores all digits that meet this criterion.
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If each letter represents a digit from 0 to 9, what might the digit marked with a question mark be?
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We know that the question mark is in the ones place, and, when multiplied by 4 results in a 2 in the product's ones digit. Only the ones place multiplication will affect our mystery digit.
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Multiplying 4 and any digit gives us all the even numbers as options, but only two of them result in a ones digit of 2
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So the mystery digit can be either 3 or 8, as either of those, multiplied by 4, results in a ones digit of 2.
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Ones digit of a multiplication, solving a factor
Test your understanding of ones digit in factor of a multiplication by practicing it! Work through the below exercises to use it in practice.