Long Multiplication What is long multiplication A number

Long Multiplication What is long multiplication? A number multiplied by a 2 digit (or larger) number e. g. 25 x 13 Is there only one way to do? Are there any tips that can help make it easier?

Methods of Long Multiplication There are 3 main methods: Lattice method Splitting (grid) method Traditional method

Lattice method – part 1 25 x 5 = ? 5 x 5 = 25 2 x 5 = 10 2 5 1 2 0 5 5 1. Make the lattice (grid) as shown 2. Multiply each number above a column by the numbers in every row 3. Write the answers in the lattice. Making sure you have only 1 digit in each triangle

Lattice method – part 2 25 x 5 = ? 2 5 1 2 0 1 2 2 + 0 = 2 5 5 5 Add along the diagonal

Lattice method – part 1 36 x 8 = ? 6 x 8 = 48 3 x 8 =24 3 6 2 4 4 8 8 1. Make the lattice (grid) as shown 2. Multiply each number above a column by the numbers in every row 3. Write the answers in the lattice. Making sure you have only 1 digit in each triangle

Lattice method – part 2 36 x 8 = ? 3 6 2 4 4 2 8 4 + 4 = 8 8 Add along the diagonal line

Lattice method – part 1 36 x 13 = ? 1 x 3 = 3 3 x 3 = 9 3 1 x 6 = 6 6 3 9 6 1 8 1 1. Make the lattice (grid) as shown 3 2. Multiply each number above a column by the numbers in every row 3 x 6 = 18 3. Write the answers in the lattice. Making sure you have only 1 digit in each triangle

Lattice method – part 2 36 x 13 = ? 3 6 3 1 4 9 6 6 + 1 + 9 = 16 6 1 8 8 1 3 Add along the diagonal line

Try the questions at the bottom of the worksheets

Grid Method – part 1 255 x 5 = ? First split the number into hundreds, tens and units. 255 splits into 200, 5 Then, multiply each of the numbers by 5. 200 x 5 = 1000 50 x 5 = 250 5 x 5 = 25 This can be placed in a grid

Grid Method – part 2 255 x 5 = ? x 5 200 50 5 200 x 5 5 x 5 1000 25 Finally, add the three numbers together to get your answer. 1000 + 250 + 25 So 255 x 5 = 1 275 = 1275

Grid Method – part 1 255 x 25 = 6375 First, split the numbers up. 255 splits into 200, 50 and 5. These go along the top of the grid. 25 splits into 20 and 5. These go down the sides. Put the numbers on the grid

Grid Method – part 2 255 x 25 = 6375 x 200 50 5 20 4000 100 5 1000 25 Add up each column, then add the resulting numbers together. 4000 + 100 1000 + 25 = = 5100 1275 6375

Try the questions again using the splitting method

Traditional method 21 x 13 = ? x 2 1 1 3 6 3 2 1 0 2 7 3 3 x 1 = 3 write down the 3. 3 x 2 = 6 write down the 6 10 x 1 = 10 write down the 10 1 x 2 = 2 write down the 2 Add the numbers

Traditional method 45 x 34 = ? 1 2 x 1 4 5 3 4 8 0 1 3 5 0 1 5 3 3 4 x 5 = 20 write down the 0, carry the 2. 4 x 4 = 16, add 2 write down the 18 30 x 5 = 150 write down the 50, carry the one 3 x 4 =12, add the 1, write down the 13 Add the numbers

Try the questions again using the traditional method