

Example: 8
4 3
 2 6 6 

STEP 1

Take 6 ones from 3 ones,
can't do

Regroup the 4 tens by trading so there are 3 tens left
in the tens column and 10 ones have been added to the original 3 to
give 13 ones

6 ones are subtracted from 13 ones

7 is placed on the answer
line in the ones place


STEP 2

6 tens can't be subtracted from 3 tens

Regroup the 8 hundreds by trading so there are 7
hundreds in the hundreds column and the 10 tens have been added to the
3 tens to give 13 tens in the tens column

6 tens are subtracted from 13 tens

7 is placed in the answer
line in the tens place


STEP 3


A few more examples of
the decomposition method 





Extension idea:
Many children love the challenge of doing subtractions mentally; indeed,
many strategies are often discussed in class. Eg
843
 266
I can first take away the 2 hundred
Now I have 643
 66
I can also take away 6 tens from 64 tens
Now I have 583  6
I can take the 6 ones from 83 ones
Now I have 577
843
 266
I can first take away 243
This leaves 600
I
now need to take away another 23
Answer 577
How many other ways can you
find? 