Whole numbers multiplication with more than three digit

Students multiply two four-digit factors with the standard algorithm, one digit of the bottom factor at a time.

• Write one partial product for the ones, tens, hundreds and thousands digit
• Shift each new row one place left with zeros: 5,651 × 80 = 452,080
• Handle zeros in a factor: 7,942 × 2,520 has a ones row of 0
• Add four rows to reach an eight-digit product

This long work builds fluency for standard 5.NBT.B.5 before 6th grade decimal products.

Print page one and walk through the worked example together, row by row.

• Say what each row means: "5,651 times 4", then "5,651 times 80".
• Keep digits in their grid columns so the sum stays aligned.
• Write commas in the final product to read it aloud, such as 46,247,784.

One or two problems per sitting is plenty. Check against page two, where each partial product can be compared line by line.

• Missing the shift: the hundreds row of 5,651 × 8,184 is 565,100, not 5,651.
• Adding misaligned rows: one digit out of its column changes the whole total.
• Skipping a zero row: in 7,045 × 3,930 the ones row is 0, but the next rows still shift.

Next, multiply three or more numbers, and estimate products to check that an answer is reasonable.