Hello, I'm Mr Firth, and I need your help today as we learn to add and subtract within ten. You can use lots of things to help you add and subtract. Counters, number lines and even your fingers. Let's ...

Count back & use the relationship between addition and subtraction to subtract within 20. Warm up with a Mystery Math Mistake to find the error in DC's addition. Use ...

Practice adding and subtracting within 20 using a Double 10-frame & number line. Represent a teen number using a number bond to solve a Mystery Math Mistake. Use Notice and Wonder with a marble game ...

Take this quiz to see how much you know about this topic already, then work through the guide and see if you can beat your score. Take a look at this number line. It shows 14 - 5 = 9. You can count ...