Decimal Arithmetic Worksheets, Grade 5 (5.NBT.B.7) – Free PDF + Answer Key

First page of the decimal arithmetic practice worksheet

Download free

PDFs print on US Letter paper. Free for classroom and home use.

Watch: Long Division With Decimals Step by Step

Key idea

Add and subtract: align the places. Multiply: multiply the digits and count the places. Divide: how many fit? Multiplying by less than 1 makes it smaller; dividing by less than 1 makes it bigger.

Sample problems

Work out 3.5 + 0.42
Work out 12.4 + 3.75
Work out 0.8 + 0.15
Work out 4.2 − 1.75

Common mistakes to watch for

Answered 15.15 or 16.05 — the carry out of the hundredths dropped.
Answered 3.36 or 2.36, by leaving the hundredths of 5 alone because “there is nothing to take from”. 5 is 5.00 and the zeros are real quantities — the same claim as the zero in a quotient (the “Dividing by two-digit divisors” sheet (Grade 5)).
Answered 1.2 — the point “lined up” rather than the places counted. It is also bigger than both factors, which is the tell.

The answer key explains each one, so you can tell what a wrong answer means.

How to use this set

Teach with the slides (about 15 minutes), or watch the video together.
Practice with the worksheet. Questions climb from fluency to application to reasoning.
Check understanding with the exit ticket.
Mark with the answer key — each answer shows the steps and the most likely mistake.