Matthew is finding factor pairs of 42. What number is missing from the table?
When we think about factor pairs, we know that they multiply together to equal something. One times 42 multiplies together to equal 42. Two times 21 multiplies together to equal 42. Six times seven multiplies together to equal 42. So the question for us becomes what times three equals 42.
We can solve this question with division. By dividing 42 by three, we can figure out three times what equals 42. Using long division, we first ask the question how many times will three go into four. It goes in one time. One times three equals three.
From there, we take three and subtract it from four. Four minus three is one. Bring down the two from 42. And we’re left with 12. We need to ask the question how many times will three go into 12. Three goes into 12 four times, because four times three equals 12.
When we subtract 12 from 12, we’re left with zero. And that tells us there is no remainder. 42 divided by three equals 14. And that means three times 14 equals 42. 14 is the missing number for the table.