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Multiplying by Single Digits

Break large numbers into parts and multiply each separately.

When to use

You need to multiply a large number by a single digit (2-9).

Steps

  1. 1.Break the large number into thousands, hundreds, tens
  2. 2.Multiply each part by the single digit
  3. 3.Add the results together

Example: 8,430 x 4

8,000 x 4 = 32,000

400 x 4 = 1,600

30 x 4 = 120

32,000 + 1,600 + 120 = 33,720

Mental approach

Work left to right: multiply the thousands first, keep a running total, then add hundreds and tens.

Pen & paper approach

Write the parts vertically, multiply each, then sum.

Tips

  • •Always work left to right — biggest chunk first gives you the ballpark
  • •For x5: multiply by 10 then halve
  • •For x9: multiply by 10 then subtract the number

Try it yourself

6,250 x 3

4,720 x 6

7,180 x 4