DECOMPOSITION - SUBTRACTION METHOD
 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 Subtract 2 hundreds from the 7 hundreds  5 is placed on the answer line in the hundreds place 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?