Second grade has been hard at work on subtraction and I thought I’d share this helpful way to explain decomposing! Since we introduce decomposing when we learn 2 digit addition many students think they can break up the first number and subtract, even if the second number is smaller. For example, if it’s 53-27 they do 50-20=30 and 3-7=4 so the answer is 34. HOWEVER, this method of explaining decomposing is a game changer. I have the students think of the first number as a bus. There are 94 people on the bus. The number we are taking away is known as the bus stops. So for this problem there’s a “tens” bus stop and a “ones” bus stop. At the first stop 30 people get off, so 94-30=64. At the second stop 8 people get off. As you see from the example, some of my students who struggle break apart the ones to help make it a tad easier. Instead of the full 8 at once, this small group broke up the number into 4 and 4 since the saw that 64 had a 4 in the ones place. The CYW on the side is something I took from a previous school I worked at, but it’s “check your work” and we spend time talking about the inverse operation. Students have become experts at adding their answer back to the second number in the subtraction problem to see if it equals the original number of “people on on the bus” if it does, they know it’s right! Eventually we don’t use terms referring to a bus or bus stop and just say decomposing but this is SO HELPFUL for strugglers or when you’re first introducing it to kiddos. Tag a teacher you think this may help—because Lord knows subtraction is rough! #teachersofinstagram #weareteachers #anchorcharts #mathteacher #secondgrade #secondgradeteacher #elementaryteacher #math #teacherlife #teachertips #firstyearteacher