Learning Intentions:

·         Fact Families / Relating Subtraction to Addition.

·         Use 100s Chart to solve problems.

·         Develop strategies for making to 100, utilizing “Friends of Ten” facts.

·         Develop Jump Strategy for Addition / Subtraction with and without 100 chart.

·         Develop Mental Strategies for Addition and finding Difference

·         Use numbers to 100 in Weight (Kg.) and Length (cm.) contexts.

·         Extensions: Working with Decimals to Tenths.

Warm Up: Friends of Ten Dudley.

Students write numbers from 1-10. Students take turns to roll 10 sided dice (0-9). Students cross of the “Friend of 10” of roll. E.g., if a 4 is rolled, students cross off 6 (4 + 6 = 10). First to have all ten numbers crossed off wins.

Model then have students work individually with group support.

Catch fish from random selection from bag.

Place fish into Ice Box.

Determine how much ice needs to be added to make Ice Box total 100Kg.

Use 100 Chart Jumping strategy (make to next ten, then by tens to 100.)

Draw Jump Strategy

Write Number Sentence for Fish + Ice = 100

Write Fact Families for the Number Sentence.

Fish + Ice = 100

Ice + Fish = 100

100 – Fish = Ice

100 – Ice = Fish

Students may determine how much room is available for ice after placing the fish in the Ice Box.

Fish (cm.) + ? = 100cm.

Extension: Use of weights and lengths to one decimal place. More advanced may also find total weight of all fish caught / ice added.

Share:

Discuss strategies for mental computation of difference (Subtraction).

Reflection: 3,2,1.

3 Things I learnt.

2 Things I am better at.

I Thing I am unsure about.

Success Criteria:

·         Students correctly find difference between fish weight and 100 using Jump Strategy on 100 chart.

·         Students model Jump Strategy Open Number Line.

·         Students write Number Sentence for Fish + Ice = 100.

·         Students write all four Fact Families for number sentence.

·         Students understand and explain connections between Addition and Subtraction.

·         Students develop fluent mental strategies for determining same.