Adding and taking away within 18 · Usually met around P1
Add or take away?
Put together: add. Taken away or compared: take away.
How to do it
Method
Put together: add. Taken away or compared: take away
5 ducks, 3 more swim up: 5 + 3 = 8
Another way
One to one
●●●●● against ●●●: 2 more
In full
First think about what happens: two groups put together, or more coming, means adding; taken away, eaten or flown off, asking how many are left, means taking away; comparing two groups, asking how many more (or fewer) one has, also means taking away, the bigger number minus the smaller. You can draw it: put together, count them all; taken away, cross them out and count the rest; compared, pair them one to one and count the ones without a partner.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
Write the number sentence: the group on the left and the group on the right put together. □ + □ = □
Fill in each box
Show the answer and working
Answer: 6，3，9
6 on the left and 3 on the right, put together: 6 + 3 = 9.
Example 2
Write the number sentence: the crossed-out ones were taken away. □ − □ = □
Fill in each box
Show the answer and working
Answer: 10，3，7
10 in all, 3 taken away (crossed out): 10 − 3 = 7.
Example 3
The top row has 14 more than the bottom row.
True or false?
Show the answer and working
Answer: False
Paired one to one, the top row has 6 extra: 10 − 4 = 6. Comparing means taking away, not adding.
Practise it in the game →Adding and taking away within 18 · Free to start, unlimited questions, no download