Page 58 - ICSE Math 4

Exercise 5.4

Find the following products.
(a) 24 × 36 (b) 51 × 34 (c) 126 × 4 (d) 254 × 8

(e) 423 × 26 (f) 318 × 14 (g) 512 × 113 (h) 221 × 172

Lattice Multiplication

We have learnt how to mul ply small numbers using Remember
la ce mul plica on. We already know that it is an easy In lattice multiplication,
method of mul plying numbers using a grid as it breaks the numbers to be
the process into smaller steps. multiplied are written
outside the lattice and
Now let’s learn how to mul ply large numbers using the the products are written
same method. inside it.

Example 6: Mul ply 345 and 15 using la ce mul plica on.

Solu on: 345 × 15

Step 1: Draw a la ce of 3 columns and 2 rows. Write the mul plicand along
the top and the mul plier along the right side of the la ce.

Step 2: Mul ply the single digits on 3 4 5
the top of the la ce by the 0 0 0
1
single digits on the side to fi ll 3 4 5
0
in the squares. Write the tens 1 2 2
digit of the product above the 5 0 5 5
slan ng line and the ones digit
below the slan ng line. If the 1 + 1 + 3 = 5 5 + 2 + 4 = 1 1 2 + 5 = 7 5
product is 1-digit number,

write 0 above the slan ng line
and the number below the
slan ng line.

Step 3: Add the numbers in the la ce diagonally. Carry the tens digit of the
2-digit sums to the next place.

Step 4: Start from the le and move towards the last digit to get the answer,
i.e., 05,175 or 5,175.

So, 345 × 15 = 5,175.

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