Counting up to Subtract Addition and Subtraction are related! They are called inverse operations. Think back to your fact families = = = = 5 I can start at the second number and count up! Try it!
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten?
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten? 180 Now let’s count by tens…get to a hundred! How many did I need to add to get to the hundred? = 200
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten? 180 Now let’s count by tens…get to a hundred! How many did I need to add to get to the hundred? = 200 Now let’s count by hundreds… get to 400! How many did I need to add to get to 400? = 400
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten? 180 Now let’s count by tens…get to a hundred! How many did I need to add to get to the hundred? = 200 Now let’s count by hundreds… get to 400! How many did I need to add to get to 400? = 400 Now I just need to get from 400 to 456. From 00 to 56 is…..56!
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten? 180 Now let’s count by tens…get to a hundred! How many did I need to add to get to the hundred? = 200 Now let’s count by hundreds… get to 400! How many did I need to add to get to 400? = 400 Now I just need to get from 400 to 456. From 00 to 56 is…..56! To find my answer, now I just add up everything I added!
Ok…Those were to easy. Let’s try these! Start at the second number and count up! Start with the ones…get to a ten! = How many did I need to add to get to the ten? 180 Now let’s count by tens…get to a hundred! How many did I need to add to get to the hundred? = 200 Now let’s count by hundreds… get to 400! How many did I need to add to get to 400? = 400 Now I just need to get from 400 to 456. From 00 to 56 is…..56! To find my answer, now I just add up everything I added!
Most of what we wrote you can do in your head. Your work should look like this. = = = = 400 Make sure you line it up!!!
Most of what we wrote you can do in your head. Your work should look like this. Let’s copy this part into our journals. = = = =
Try this one. = 390 Hint: start with the bottom number. Count by ones. Stop at the first ten. Add on by: ones tens hundreds final number
Try this one. = = 400 Hint: start at 390. Count by tens. Stop at the first hundred.
Try this one. = = = 800 Hint: start at 400. Count by hundreds. Stop at 800. (Look at your top number to see why.)
Try this one. = = = = 800 Hint: start at 800. Stop at 45. (Look at your top number to see why.)
Try this one. = = = = 800 Hint: Line them up! Then, add!
Try this one. = = = =
More practice. 1, 4, ,874
More practice. 1, 4, ,874
More practice. 1, 4, ,874 Do the rest with paper and pencil by yourself. I might ask you to come work with me on the floor.
Put up your pencil and get out your red pen!
More practice. 1, 4, ,874 2,768