Multiply a Multi-Digit Number by a One-Digit Number

Students multiply whole numbers up to four digits by a one-digit whole number using strategies based on place value and properties of operations, including the standard algorithm with regrouping. They connect the partial products strategy to the standard algorithm.

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Real questions from this skill, graded here. No account, and nothing is saved.

Grade 4 · Multiplication of Multi-Digit Numbers · question 1 of 3

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20 rungs. A star at the top.

32 × 5 = .

How it is taught

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Split the multi-digit factor by place.

Multiply each place, then add.

Read it: Split by place, multiply each part

47 × 3: split 47 into 40 + 7. 3 × 40 = 120 and 3 × 7 = 21, and 120 + 21 = 141. 47 × 23 splits both numbers, into 4 parts.

Split each number by place: 47 = 40 + 7.
Multiply every part: 3 × 40 = 120 and 3 × 7 = 21.
Add the parts: 120 + 21 = 141.

The 4 in 47 is 4 tens, so 3 × 40 is 120, not 12.

The parts together are the whole rectangle, so their products add up to the whole product.

With 2 two-digit numbers there are 4 parts: every part of one number meets every part of the other.

Split by place, multiply every part, and add the parts.

Multiplying the 4 in 47 as a 4: 3 × 4 = 12 and 3 × 7 = 21, written side by side as 1221.

The 4 is 40: 3 × 40 = 120. Then add the parts: 120 + 21 = 141.

2473 × 6 = ___ — 14,838. Split by place and multiply every part: 12,000 + 2400 + 420 + 18 = 14,838.

234 × 6

Picture six boxes of crayons. Each box has two hundred thirty-four crayons. How many crayons in all?

We can stack two hundred thirty-four on top and times six below, just like addition.

Start in the ones place. Six times four...

is twenty-four. Write the four, and carry the two to the tens.

Now the tens. Six times three is eighteen.

Add the two we carried — that's twenty. Write zero, carry two to the hundreds.

Last column. Six times two is twelve.

Add the two we carried — fourteen. Write all fourteen, since this is the last column.

Grade 4 · Six boxes of 234 crayons

Two hundred thirty-four times six is one thousand four hundred four. Six boxes hold one thousand four hundred four crayons!

What you see

While they climb, your page writes one true line to ask about tonight, and a short note each Sunday.

MayaGrade 3 · Mathematics

Did you know?

A chessboard has 64 squares — share them out between the 8 rows and each row holds exactly 8.

Today’s goal: 1 star — one skill mastered, every rung of its ladder climbed
Climbing now: Divide within 100

An example student.

MayaGrade 3 · Mathematics

Maya earned 2 stars this week — Interpret multiplication as equal groups, which took 6 answers over 3 days before its star landed 3 days ago and Multiply by 6, 7, 8 and 9. Next up: Divide within 100.

An example week.

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Standard

CCSS.4.NBT.B.5

Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers

Grade 4

Quoted from the Common Core State Standards.

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What a star here means

A star here is the top of a twenty-rung ladder, in four blocks of equal length — three of facts and one of the skill used in a real question — where a right answer climbs one rung and a wrong one drops back to the start of the block, never below it. The star is kept for good. How we grade

All of Grade 4

This is one rung of 71 in Grade 4 mathematics, in the order they build on each other.

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