Mental Multiplication Strategies Maths Grade 3 | Orchids

Mental Math

Mental Multiplication Strategies

Mental math is a skill that helps students to do math in their heads without using paper and pencil.

• Mental Math is useful in school and everyday life.
• It also helps to do calculations faster.

In multiplication,

• The number with which we multiply is called the multiplicand.
• The number which is multiplied by the multiplicand is called the multiplier
• The result of a multiplication is called the product.

Method 1:

• Multiply each number from left to right with the multiplier. Let us discuss with an example.

Example :

a) 42 Ã— 7

Method 2:

• Round off the multiplicand to the nearest ten
• Then do the multiplication
• After that, multiply the reduced or additional value of the rounded off number with the multiplier.
• Then subtract/add the product from the previous one. Let us discuss with examples.

Example :

a) 78 Ã— 3

b) 44 Ã— 6

a) 78 Ã— 3 = (80 â€“ 2) Ã— 3

b) 44 Ã— 6 = (40 + 4) Ã— 6

Method 3:

• Split the multiplier into factors.
• Multiply the numbers multiplicand with the first factor
• Then multiply the product of the previous multiplication with the second factor.
• Continue the same process with all the factors.
• Let us discuss with examples.

Example :

a) 24 Ã— 8

b) 25 Ã— 44

a)

 24 Ã— 8 = 24 Ã— 2 Ã— 4 = 48 Ã— 4 =

So, 24 Ã— 8 = 192

b)

 25 Ã— 44 = 25 Ã— 4 Ã— 11 = 100 Ã— 11 = 1100

So, 25 Ã— 44 = 1100

Method 4:

• Break the multiplier as the sum/difference of the nearest ten/ hundred and a one-digit number.
• Multiply by each from right to left.
• Let us discuss with examples.

Example :

a) 46 Ã— 12

b) 23 Ã— 18

a) 46 Ã— 12 = 46 Ã— (10 + 2) =

So, 46 Ã— 12 = 552

b) 23 Ã— 18 = 23 Ã— (20 - 2)

So, 23 Ã— 18 = 414

Method 5:

• Round up the multiplier to the nearest hundred.
• Multiply the rounded-up value and the amount rounded up from left to right.
• Subtract the products

Example :

27 Ã— 96

27 Ã— 96 = 27 Ã— (100 â€“ 4)

Method 6:

• Express both the multiplier and multiplicand as the sum of the nearest ten and a one/ two digit.

Example :

35 Ã— 22