Mental math guide

How to multiply two-digit numbers mentally

For two-digit multiplication, the easiest mental math trick is to split each number into tens and ones. With 23 x 45, think of 23 as 20 + 3 and 45 as 40 + 5.

Mental math diagram for 23 x 45 split into 20, 3, 40, and 5

Step 1: split the numbers

Breaking numbers apart makes two-digit multiplication easier because each small product is simple to calculate in your head.

23 split into 20 and 3, and 45 split into 40 and 5

Step 2: calculate the four partial products

20 x 40 = 800
20 x 5 = 100
3 x 40 = 120
3 x 5 = 15

These partial products are the core of the distributive property. Instead of trying to hold the full calculation at once, you solve four easier pieces.

Partial products for 23 x 45

Step 3: add the results

Add 800 + 100 + 120 + 15 to get 1,035. This method works well for mental calculation practice because it keeps every step predictable.

23 x 45 equals 1,035 using partial products

Practice with Mentalc

Use the Mentalc multiplication settings to practice two-digit multiplication, arithmetic drills, and mental math speed training.

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