# A little bit more/A little bit less Teaching Notes

These exercises and activities are for students to use independently of the teacher to practise number properties.

### Curriculum Reference:

Number, level 2-3

### Numeracy Project Book Reference:

These exercises and activities follow from a teaching episode based on Book 6 Page 15 and are for those students who are able to use the associated number properties.

### Prior knowledge. Students should be able to…

• Multiply basic facts up to the 10 times tables
• Multiply basic facts with tens, hundreds and thousands eg 3 x 60, 5 x 200
• Use addition and subtraction facts up to 20

### During these activities students will meet:

Solving multiplication problems by putting some on, using tidy numbers (Ex 1, 3, 5)
Solving multiplication problems by taking some off, using tidy numbers (Ex 2, 4, 6)
Solving multiplication problems by taking some off or putting some on (Ex 7)
Using the strategy of compensation to solve multiplication problems (Ex 8, 9)

### Background:

The exercises have been set up in the following way.
Exercises 1 – 7, Student has been given a tidy number statement eg 5 x 20 = 100 and they use this given fact to find the answer to eg 5 x 19 or 5 x 22 (by compensation – add on a little or subtract a little).
Exercise 1: Multiply by a “ten number”. Add on a little, value added on is less than ten.
Exercise 2: Multiply by a “ten number”. Subtract a little, value subtracted is less than ten.
Exercise 3: Multiply by a “ten number”. Add on a little, value added could be more than ten.
Exercise 4: Multiply by a “ten number”. Subtract a little, value subtracted could be more than ten.
Exercise 5: Multiply by a “hundred number”. Add on a little, value added could be more than ten.
Exercise 6: Multiply by a “hundred number”. Subtract a little, value subtracted could be more than ten.
Exercise 7: Multiply by either 25 or 15 and either add on a little or subtract a little.
Exercise 8: Students are given a problem to solve using the compensation strategy.
Exercise 9: Students are to make up their own problems that use the same strategy.

### Number generalisation:

Ideas that can be developed from this activity:
Eg.
3 x 28 = 3 x 30 – 3 x 2
3 x a = 3 x (a + b) – 3 x b
3 x 31 = 3 x 30 + 3 x 1
3 x a = 3 x (a-b) + 3 x b

PDF (105KB) or Word (64KB)

PDF (107KB) or Word (55KB)

Follow the same model as the practice exercises.

### Related games/activities:

Loopy Sheets:PDF (96KB) or Word (132KB)

Loopy master:PDF (19KB) or Word (45KB)

### Figure It Out References

Number Link 2 – Year 7-8 – Page 6 Planting with the Whanau