addition and subtraction on a number line links between the model and appropriate ‘vertical’...
TRANSCRIPT
Addition and subtraction on a number line links between the model and
appropriate ‘vertical’ method
Janine Blinko
421-273
421-273
421
-200
221
In which case they need to be fluent in subtracting multiples of 100 from any number……
Equivalent written recording-formal version
421-273221 -200
421-273
and fluent in subtracting multiples of 10 from any number including crossing the hundreds boundaries……
Equivalent written recording-formal version
421-273221 -200151 -70
421
-200
221
-70
151
421-273
-3
148 421
-200
221
-70
151
Equivalent written recording-formal version
421-273221 -200222 -70148 -3
91-68
+2
68 91
+1
23
+20
70 90
It is 11.25. My cake will be ready at 1.15. How long do I have to wait before it is ready?
+5 mins
11.25 1.15
+1 hour
1hour 55 minutes
+30 mins
11.30
+15 mins
1.0012.00
421-273
+7
273 421
+100
148
+20
280
+21
400300
Equivalent written recording-formal version
421-273 7 280 20 300100 400 21 421148
421-273
-3
148421
-200
221
-70
151
Equivalent written recording-formal version
421-273221 -200222 -70148 -3
421-273
-3
148 421
-200
221
-70
151
Equivalent written recording-formal version
421-273221 -200222 -70148 -3
148+273
148+273
148
+200
348
In which case they need to be fluent in adding multiples of 100 to any number……
Equivalent written recording-formal version
148+273348 +200
148+273
148
+200
348
and fluent in adding multiples of 10 to any number including crossing the hundreds boundaries……
+70
418
Equivalent written recording-formal version
148+273348 +200418 +70
148+273
148
+200
348
+70
418
+3
421
Equivalent written recording-formal version
148+273348 (+200)418 (+70)421 (+3)