## Why parents choose Splash Math for their fourth graders?

#### Personalised Learning

Intelligently adapts to the way each child learns

#### Fun Rewards

Get coins for each correct answer and redeem coins for virtual pets

#### Actionable Reports

Monitor progress with iPhone app, weekly emails and detailed dashboards

13.

# Multiply 2 Digit by 2 Digit (Numbers up to 40)

- 4th Grade MathSo far, Grade 4 children have learned to multiply numbers up to 4 digits with a 1-digit number. It is time to introduce them to the multiplication of two 2-digit numbers. This immersive game builds on their understanding of utilizing the area models to carry out multiplication of double digit numbers.

**What’s inside?**

- Begin by using the distributive property of multiplication to break down the multiplication process.

- Work with area models (the box method) to better understand how the standard algorithm of multiplication works.

**Real-World Application**

Teachers calculate the number of sheets to be copied if they want to distribute, say, 15 worksheets each to all 26 of their students. Or, when planning a birthday party, parents and children want to find out the total amount they’d spend on a guest list of 18 when the per head cost is $12. All such instances require the multiplication of two 2-digit numbers and it helps to master this skill to be able to make such simple decisions with ease.

**What’s next?**

In this game, children work with 2-digit numbers up to 40. They are now set to carry out multiplication operations with bigger numbers - up to 70 and 100 - using the same techniques they learned here.

#### Cool Fact

Here’s a cool way to quickly multiply any two 2-digit number with 11 – just add the digits of the two digit number and place the sum bang in the middle of these digits. Take a look: 23 x 11 = 253. For numbers where the sum adds to more than 9, just carry the 1 to the first digit.

### Common Core Alignment

**4.NBT.5**Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.