The idea in brief. Multiply each place and include its carried value in the next place, even when a digit is zero. Multiply each place, then include the carried value. In the lesson. In Primary 2, you learned to add with renaming. Today, we will multiply by a one-digit number, one place at a time, starting with the ones. Multiply one place at a time, starting with the ones. Multiply first, then add the number on top.
Lesson video, with the working
Multiply by one digit
5 min 07 s
The film teaches 3 questions in turn. Each question shows first; its working is written as the film explains it.
How do P3 children solve 3-digit by 1-digit multiplication questions?
This page teaches multiplying a number of up to 3 digits by a 1-digit number in columns, the MOE Primary 3 outcome on multiplication algorithms.
What your child learns here
This page teaches multiplying a number of up to 3 digits by a 1-digit number in columns, the MOE Primary 3 outcome on multiplication algorithms. It builds on the times tables and on renaming in addition.
Multiply one place at a time, starting with the ones.
Rename the product in each place: 7 ones times 4 is 28 ones, so write 8 and carry 2 tens.
Multiply first, then add the carried digit, never the other way round.
Handle a 0 in the middle of a number, as in 406 times 3, where the tens place still receives the carried 1 and the answer is 1218.
Recognise equal groups in a word problem and write the multiplication.
Does the answer make sense?
When the answer is a product, it must be bigger than the number being multiplied, since every multiplier here is 2 or more. Your child can also check the ones digit: in 586 times 7, 6 times 7 ends in 2, so the product must end in 2 too.
How to practise these questions
The Basic questions practise multiplying each place in turn, from the ones upwards. The Intermediate questions add regrouping, where a product in one place carries into the next. The Challenge questions regroup in more than one place or put the multiplication inside a short story. If multiplying stalls, watch that question's solution film and attempt it again later from Revision.
Questions parents ask
Is 3-digit by 1-digit multiplication in the Primary 3 syllabus? Yes. The MOE Primary 3 syllabus lists multiplication and division algorithms up to 3 digits by 1 digit. This page covers the multiplication half; division is on the next pages of the chapter.
Does my child need to know the times tables first? It helps a great deal. Each place is multiplied using a table fact, so a slow table fact slows every step. The tables of 6, 7, 8 and 9 have their own chapter.
Where does the carried number go in column multiplication? It is written small above the next place to the left, then added after that place has been multiplied. Multiply first, then add the carried number.
