Find a Starting Amount Before Some Leave

Supplied materials

• Paper and a pencil; drawing and spoken explanations are welcome. An adult may read directions and options aloud.
• Supplied worked-case record: After 5 cards are removed, 8 remain.
• All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

When items leave, the start was larger than the remaining amount. A missing-start story gives the removed part and the leftover part. Rejoin those two parts to reconstruct the original whole rather than subtracting again from the leftovers.

Write start − removed = remaining. Add the removed amount to the remaining amount to find the start. Check by taking the removed amount away from your reconstructed whole.

Both the removed and remaining cards belonged to the start. Do not subtract the removed part from the leftovers. Draw separate removed and remaining groups, then circle them as one starting whole.

1. Draw separate removed and remaining groups, then circle them as one starting whole.
2. Follow the worked example. Point to each number or shape feature and say what it tells you.
3. Write start − removed = remaining.
4. Try the question and then the three practice questions. Check your answers and explain any change you make.

Check your reasoning

Your answer is temporary and is not saved to an account. Download your current answer before leaving or reloading. Written work on paper or in another app stays in your own file.

Take it further

Six are removed and nine remain. Expected: the starting amount was 15.

Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.