Adding whole numbers - How to add whole numbers

Students add and subtract multi-digit whole numbers with the standard column method.

• Add three numbers of different lengths, up to six digits
• Check the sum against three close answer choices
• Subtract twice in a row: the first difference becomes the next starting number
• Regroup across zeros, as in 9,205 - 8,600

Fluently adding and subtracting multi-digit whole numbers with the standard algorithm is standard 4.NBT.B.4, which 6th graders extend to decimals.

Print pages one and two and keep the key pages aside.

• Line up the digits on the right, ones under ones, before adding; 705 and 550,329 do not have the same length.
• For each subtraction chain, copy the layout of the solved example: the middle line is the first difference.
• Compare the boxed answer with the three choices only after working it out.

Note: the heading on page one says subtracting, but every exercise there is an addition. Check with pages three and four, which show the carries.

• Lining up on the left: writing 705 under the first digits of 550,329, which adds hundreds to hundred-thousands.
• Losing a carry: 3,759 + 105 + 3,677 gives 6,541 instead of 7,541 when the carry from the hundreds is dropped, and 6,541 is one of the choices.
• Subtracting the smaller digit from the larger: in 39,860 - 4,937, writing 7 - 0 = 7 in the ones instead of regrouping.

Next, move on to multiplying whole numbers.