Multiplying Numbers Beyond Ten - Mental Math with Arthur Benjamin

Multiplying numbers beyond ten using mental math becomes easier when you apply patterns and break numbers into manageable parts. One of the most effective strategies is decomposition. For example, to solve 14 × 6, think of 14 as 10 + 4. Multiply 10 × 6 and 4 × 6, then add the results. Another method is doubling and halving: if one number is even, halve it and double the other to keep the product the same. For instance, 16 × 15 becomes 8 × 30, which many people find simpler. You can also use near-ten strategies, helpful when one number is close to 10, 20, or 50. For example, 19 × 7 can be seen as 20 × 7 minus 7. Estimation supports quick checks by rounding numbers to the nearest ten. With these mental tools, multiplying larger numbers becomes faster, clearer, and more intuitive, especially in everyday problem-solving.