Super Smart Multiplication: The Partitioning Power-Up! (2-digit x 1-digit)

Hello Multiplication Pros! Get ready to unlock another amazing mental maths superpower: using partitioning to multiply a 2-digit number by a 1-digit number in your head! “Partitioning” just means breaking the bigger number into its tens and ones. This trick turns one big multiplication into two smaller, easier ones that you already know!

The Secret: Break Apart, Multiply, Then Add!

When you see a problem like 13 × 3, instead of trying to do it all at once, we can cleverly break apart (partition) the 2-digit number (13) into its tens and ones.

Let’s Solve: 13 × 3 (Thinking (10 × 3) + (3 × 3))

Here’s how this smart strategy works:

• The Problem: We want to solve 13 × 3.
• Step 1: Partition the 2-digit number. Break 13 into its tens and ones:
  • 13 = 10 (one ten) + 3 (three ones).
• Step 2: Multiply the tens part by the 1-digit number. Take the tens part (10) and multiply it by 3.
  • 10 × 3 = 30. (You know how to multiply by 10!)
• Step 3: Multiply the ones part by the 1-digit number. Now take the ones part (3) and multiply it by 3.
  • 3 × 3 = 9. (You know this basic fact!)
• Step 4: Add your two answers together. Now add the results from Step 2 and Step 3.
  • 30 + 9 = 39.
• The Answer: That means 13 × 3 = 39!

You just solved it by breaking it into easy pieces!

Another Example: 24 × 4

• Problem: 24 × 4
• Step 1: Partition 24. 24 = 20 + 4.
• Step 2: Multiply tens part by 4. 20 × 4 = 80. (Think: 2 × 4 = 8, then add the zero, so 80)
• Step 3: Multiply ones part by 4. 4 × 4 = 16.
• Step 4: Add the results. 80 + 16 = 96.
• Answer: So, 24 × 4 = 96.

Practice Your Partitioning Multiplication! (18 Challenges)

Ready to try this clever partitioning strategy? For each problem below, multiply the 2-digit number by the 1-digit number. Remember to partition the 2-digit number into tens and ones, multiply each part, and then add your results together!

(Your web app with the 18 questions will go here. Questions should be like “17 × 4 =”, “26 × 3 =”, “45 × 2 =”, encouraging the mental partitioning strategy.)

Why is This Partitioning Trick So Great for Mental Maths?

• Turns Hard Sums into Easy Ones: It breaks down a bigger multiplication into two smaller ones using facts you likely already know (like multiplying by tens and basic times tables).
• Boosts Your Mental Speed: With practice, you can do these steps very quickly in your head.
• Builds Strong Number Sense: You get better at seeing how numbers are made up of tens and ones and how they work together.
• Foundation for Bigger Multiplication: This strategy is similar to how parts of bigger written multiplication methods (like the grid method) work!

Tips for Grown-Ups: Helping with Multiplication by Partitioning

This mental strategy uses the distributive property of multiplication (e.g., a × (b + c) = (a × b) + (a × c)) in a child-friendly way. It relies on secure knowledge of basic multiplication facts and multiplying by multiples of 10.

• Ensure Basic Facts are Strong: Children need to know their times tables (e.g., up to 10×10) and how to multiply by 10 easily before tackling this effectively.
• Visualise the Partition: At first, write it out: 13 × 3 = (10 × 3) + (3 × 3). Use different colours for the tens part and the ones part.
• Use Place Value Cards or Blocks: Show how 13 is made of one ’10’ and three ‘1s’. Then show multiplying each part by 3.
• Verbalise the Steps Clearly: Encourage children to say the steps: “First I do 10 times 3, that’s 30. Then I do 3 times 3, that’s 9. Then I add 30 and 9, which is 39.”
• Connect to the Grid Method (if taught): Show how this mental strategy mirrors the steps in the grid method of multiplication, which is a visual way of partitioning.