How_To_Be_Good_At_Math

CALCULATING • EXPANDED COLUMN ADDITION 85

When we add together

the 8 and 5, we’re

actually adding 80 and 50.

The answer is 130. On a new

line, write 1 in the hundreds

column, 3 in the tens column

and zero in the ones column.

Add the tens

together

385

157

12

130

H T O

Now we have added the

digits in the bottom row

to the digits in the top row,

we add the three lines in our

answer together:

12 + 130 + 400 = 542

So, 385 + 157 = 542

Next, we’re going to add

the hundreds together.

We add 100 and 300 to give

400. On a new line, write 4 in
     the hundreds column, 0 in the
     tens column, and 0 in the
     ones column.

Add the hundreds

together

Answers on page 319

TRY IT OUT

Add it up

Now you have learned this useful

method for adding difficult

numbers, why don't you give

these calculations a go?

385 + 157 = 542

7256 + 4715 =?

948 + 642 =?

547 + 276 =?

Add the three

lines in the

answer together

385

157

12

130

400

385

157

12

130

400

542

H T O

H T O

Expanded column addition

is just like partitioning – we

break tricky numbers into

ones, tens, and hundreds.

084_085_Expanded_column_addition.indd 85 29/02/2016 18:02