Published Oct 31, 2026
The middle picture shows 42. The others show 24 and 40.
Made with the help of AI from public curriculum standards, then checked. Mistakes can slip through, so please look it over before use. Found one? Tell us and we will fix it.
Base ten blocks show what a two-digit number really means: a tall bar is ten small cubes stuck together, and the loose cubes are ones. On this page your child counts bars and cubes to write six numbers, then works the other way and draws quick blocks for 34, 18, and 46. The last task asks which picture shows 42, next to 24 and 40, which are classic mix-ups. Seeing and drawing tens and ones builds the place value sense first graders need before adding two-digit numbers.
Common Core 1.NBT.B.2: Reading a 2-digit number as groups of ten plus leftover singles
Short descriptions in our own words. About our standards.
Count the bars by tens, 10, 20, 30, and then count on the cubes one at a time: 31, 32, 33. Counting every bar as one is the most common error, so ask: how many cubes are in one bar? When drawing, a simple line for a ten and a small square for a one is enough; nobody needs to draw ten little cubes. If you have real blocks or linking cubes, build each number before writing it.
Easier: Start with numbers below 30 and real objects: snap linking cubes into towers of ten, or bundle ten craft sticks with a rubber band.
Harder: Ask your child to show 34 in a second way, such as 2 tens and 14 ones, or to draw the number that is 10 more than each picture.
The middle picture shows 42. The others show 24 and 40.
It is made for 1st Grade (ages 6-7). The level is ★★ medium, so it suits children who already know the basics.
About 20 minutes, about the length of a short homework task or a warm-up at the start of a lesson.
On the second page of the PDF and on this page under Show the answer key. To print for a whole class, print only the first page of the PDF.
Common Core 1.NBT.B.2 (reading a 2-digit number as groups of ten plus leftover singles).
Yes. Print as many copies as you need for your own children or students. Please do not resell it or upload it to other websites.
