Addition Mine

Choose a mode

Build the sum using each digit's − / + buttons (hundreds, tens, ones), or drag up over a column to add a crystal. When a column fills past 9, an ore cart rides the rail to carry the group to the next place. Press Check to check

3D math game · Best for grades 2-4

Addition Mine

Addition Mine puts place-value columns right in front of you. Students build a target sum by filling a ones column, tens column, and hundreds column with ore crystals. When a column overflows ten, an ore cart carries the group to the next place — so regrouping becomes visible instead of abstract.

What students practice

Addition Mine builds the concrete understanding of regrouping (carrying) that underpins column addition. By physically filling columns and watching ten units bundle into one at the next place, students stop confusing digit positions and start seeing why the algorithm works.

  1. Read the two numbers shown at the top of the mine shaft.
  2. Use the −/+ buttons (or drag up) to add ore crystals to the ones, tens, and hundreds columns.
  3. When a column reaches ten crystals, watch the cart carry them to the next column — that is regrouping.
  4. Keep adding until the total matches the target sum, then press Check.

How to use it at home or in class

Adding 47 + 36: fill 7 ones and 6 ones — the cart carries ten to the tens column, leaving 3 ones. Then add 4 tens and 3 tens plus the carried one to get 8 tens. Result: 83.

Students often add all the digits without considering place value, writing 47 + 36 = 713 instead of 83. Watching the cart move ten crystals physically into the next column corrects this column-blindness before it becomes a habit.

Use it for individual practice, paired work, or a short class demonstration before worksheets.

Start with the game above, then continue with written practice to reinforce the skill.

Common questions

Which grades is Addition Mine designed for?
It suits grades 2–4, covering 2-digit and 3-digit addition with regrouping — the core progression in early elementary arithmetic.
Does the game always require regrouping?
No. Some problems have no carrying; others require carrying once or twice. The mine shaft only shows the cart animation when a column actually overflows ten.
How is this different from Balance Scale?
Addition Mine builds a sum step by step using place-value columns and regrouping. Balance Scale requires students to find a total and match it by selecting weights — the emphasis is on equality rather than column arithmetic.