Standard Algorithm Addition Subtracti

Can you subtract 5 from 4?

• no
• yes

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

What should I do so I can subtract the ones column?

• you need to subtract 4 from 5
• you need to un-bundle a ten so we get 10 more ones. 
• we should subtract the 5 from the 7

Tags

CCSS.2.NBT.B.7

Okay we took a ten from the 6 and left 5 tens. Now what?

• you should add the ten ones you un-bundled to the four ones. so we have a 15 above the 4
• put a 10 above the 4 and subtract 5 from the 10
• cross out the 4 and write 14 over it

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Okay I crossed out the 4 and wrote 14 over it.... now can i subtract the 5?

• yes, you can subtract the 5 from the 6.
• yes, you can subtract the 5 from the 14
• yes you can subtract the 5 from the 7

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Awesome sauce! we did some subraction. Now we can subtract the 5 from the 7 in the tens column right

• yes
• no

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

oh okay I need to subtract the 7 from the 5... I can do that... oh wait I can't. What do I now?

• make the 5 above the 6 into 15 and subtract the 6.
• Take a hundred from the 7 hundreds and unbundle it so we can add it the 5 tens

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Okay I took away the hundred.... and crossed out the 7 and re-wrote the hundreds above as a 6 so I wouldn't forget...now what?

• Now you can make the 5 a 15
• now cross out the 5 and repkace it with a ten

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

Alright now what can I do?

• just give up
• make the 6 a 16 then subtract the 5
• subtract the 7 from the 14...then subtract the 5 from the 7

Check the work. Is it correct?

• yes
• no

Tags

CCSS.2.NBT.B.7

CCSS.3.NBT.A.2

How many tens are in a hundred?

• all of them
• 6
• 10
• 12

Tags

CCSS.2.NBT.A.1B