Page 11 - prim 4 كامل

Delta Modern Language Schools

Maths Department
Prim 4 2023-2024

3) Subtraction strategies using the number line

a) Counting back with decomposition :
(Starting from minuend back according to the subtrahend)

Ex. : 384 - 162

Step 1 : Draw an open number line and write the minuend at right end of the

line

384

Step 2 : Decompose the subtrahend (162 = 100 + 60 + 2 )

Step 3 : Count back from the minuend -100 -60 -2

using the decomposition of subtrahend 222 322 382 384

b) Counting up with decomposition :

(Starting from subtrahend till reach the minuend )

Ex. : 384 – 162

Step 1 : Draw an open number line and write the subtrahend at left end of the
line

162

Step 2 : Decompose the minuend (384 = 300 + 80 + 4)

Step 3 : Count up from the subtrahend +200 +20 +2 384
To the minuend 162 362 382
Step 4 : Add the jumps together to get

the difference ( 200 + 20 + 2 ) = 222

4) Addition and subtraction with regrouping

Ex.1 : 358 + 264 11

Step 1 : Add ones ( 8 + 4 = 12 ones ) 358

16 ones = 1 ten and 2 ones + 264
Step 2 : Add tens ( 5 + 6 + 1 = 12 tens ) 622

12 tens = 1 hundred and 2 tens

Step 3 : Add hundreds ( 3 + 2 + 1 = 6 hundreds )

11