# What number can go in the blank? 37, 49, __, 63, 78This was on my son's 1st-grade test. We are all stumped.

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Based on this being on a first grade test, I am going to suggest you contact the teacher. There is either a misprint or a section missing. Your son is probably not doing multiplication or division yet. Now, you can get it to workout if you add 37 + 12 = 49 + 1 = 50 + 13 = 63 + 1= 64 + 14= 78 so if they are working on some sort of a pattern lesson it might be this and then the blank would be a 50- but the 64 is not included so that would be my only idea. I teach grade 6 math, I have taught math for 19 years in grades 3-6 so I am unsure of the reasoning on this. Please request info from the teacher.

I too thought this must be an error, but as the other teacher said, first graders are probably expected to only recognize patterns at this point. So I thought the error might be that 78 should be 75-- that the pattern is raising the first number (in the tens place) one, and raising the second number by two: 37, 49, 51, 63, 75. So the pattern is 3,4,5,6,7 for the tens place, and 7, 9, 11, 13, 15, with the idea that the first graders would mark the rising number in the one's position.

I can understand how the teacher might accidentally write 78 instead of 75, because as the teacher is increasing the one's place, she was probably writing the pattern while thinking the increases in her head, maybe thinking to herself, okay, so 37, up one 4 up two 9, 49, then 5 and 9 up 2, 11, so 51, then 63, and 63, that's 7 and 5, and as she's thinking of going up to 5, she inadvertently adds the 5 and writes 78.

Thanks for your responses. Here is the response from the teacher:

The answer on the math test had to be a number with a 5 in the tens place. The oral direction that they received during the test was to write a number with a 5 in the tens place. They could have had any number between 50 and 59 as a correct answer.

If we go on the following assumption that we have a series made up of numbers from the 30, 40, 60, and 70-range, that means that we can fill in the blank with any number from the 50 range: 50, 51,...58, 59.