Early word problems
Solve one-step word problems involving addition and subtraction to 20, including missing-number problems
What a learner can do afterwards
- Solve one-step adding and taking-away stories within 20, including zero
- Find a missing start, added amount or taken-away amount in an addition or subtraction equation within 20
- Use counters or drawings to represent joining, taking away and parts of a total
1 · Read
Read the story. Find what the question asks and use the amounts you need. Some stories give an extra number you do not need. Draw things or use counters. When groups join, add and count on. When things go away, draw the start, cross out that many and count what stays. Taking away zero leaves the same number.
Mia has 18 apples and eats 7. Draw 18 apples and cross out 7. Count the apples still there: 11. So 18 - 7 = 11.
A box stands for a number you need to find. The equals sign means both sides have the same amount. In 4 + [ ] = 10, find how much to add to 4. Count on from 4 to 10, one at a time. You count 6 more, so the box holds 6. This also finds a missing part of a total.
To find a missing start, work back from the end. Some blocks get 3 more and become 10. Remove the 3 new blocks: 10 - 3 = 7 at the start. Some blocks lose 4 and have 9 left. Put the 4 back: 9 + 4 = 13 at the start. Write this as [ ] - 4 = 9 or 9 = [ ] - 4.
To find how many went away, subtract what stayed from the start. There were 16 blocks and now 10 remain. The missing amount is 16 - 10 = 6. Check: 16 - 6 = 10. Write the story as 16 - [ ] = 10 or 10 = 16 - [ ].
Check a missing number by putting it into the equation. For [ ] - 7 = 8, add the 7 taken away to the 8 left: 8 + 7 = 15. Check: 15 - 7 = 8. A starting amount of 1 cannot fit this story because there are not 7 things to take away.
Find the missing number by reading carefully and checking your answer.
This lesson, practice bank and flashcards were written for the LightMySky dataset.
The readings, extra questions and flashcards were written for the LightMySky dataset.
More to read
Show the story with counters
A counter can stand for one thing in a story. A tray holds 15 biscuits. Six biscuits are taken off the tray. Start with 15 counters and move 6 aside. Count the counters still on the tray. There are 9. The counters show both parts: 6 taken away and 9 left.
Find the amount added
There are 9 beads on a string. You want 15 beads. Write 9 + [ ] = 15 to show the missing amount. Count on from 9: 10, 11, 12, 13, 14, 15. You counted 6 more beads. Check by adding: 9 + 6 = 15.
Find the starting group
A bag held some shells. You took out 3 shells, and 8 stayed in the bag. To find the start, put the shells you took out together with the shells still in the bag. Three and eight make eleven. The bag started with 11 shells. Check the story: take 3 from 11 and 8 remain.
Find what was taken away
A box started with 10 crayons and now holds 6. Find how many were taken out. Six crayons stayed, so count from 6 up to 10. Four more crayons complete the starting group. Check: 10 - 4 = 6. You can also write 6 = 10 - 4. Both sides show the same amount.
2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.