Addition & Subtraction: Inverse Operations Explained
Year 1 Mathematics Understanding how addition and subtraction work together 30 minute lesson
WALT (We Are Learning To)
Model addition and subtraction to understand inverse operations Use inverse operations to record related addition and subtraction facts Check our work by switching between adding and subtracting
What Do You Notice?
Look at your hands Count your fingers What happens when you put both hands together? What happens when you hide one hand behind your back?
Understanding Addition First
Start with the parts (5 fingers + 5 fingers) Add parts to combine them together Write the equation: 5 + 5 = 10 Now subtract to check: 10 - 5 = 5
Hands-On Practice: Building Numbers
Use counting blocks or toys Make a group of 3 Make a group of 2 Put them together - how many? Now take away the group of 2 - how many left?
Understanding Subtraction First
Start with the total (10 fingers) Subtract a part to separate (hide 5 fingers) Write the equation: 10 - 5 = 5 Now add to check: 5 + 5 = 10
Addition and Subtraction are Friends!
{"left":"3 + 4 = 7\n4 + 3 = 7\nAddition puts things together\nWe end with the total","right":"7 - 4 = 3\n7 - 3 = 4\nSubtraction takes things apart\nWe start with the total"}
Let's Practice Together!
I'll give you an addition problem Solve it together Then write the subtraction check 6 + 2 = ? Now check: 8 - 2 = ?
Remember This!
Addition and subtraction are like putting puzzle pieces together and taking them apart They use the same numbers in different ways We can always check our work by using the opposite operation
What We Learned Today
Addition and subtraction are inverse operations We can check addition by subtracting We can check subtraction by adding The same three numbers appear in both equations Our fingers show us bonds to 10 every day!