## Three solutions:

^{(I’m assuming that your data are in cells A1:B22.)}

### 1. Conditional Formatting

- Set
`C1`

to `=B1`

.

(If your data don’t begin in column 1,
and the row before the first data row doesn’t have numbers in it,
you can use the next formula for the entire column.)
- Set
`C2`

to `=IF(A1=A2, C1+B2, B2)`

and drag/fill down to `C22`

.

This will set column `C`

to be a running total for the matching numbers;

i.e., `C1`

= 50, `C2`

= 220, `C3`

= 320, `C4`

= 900, `C5`

= 500, etc.
- Select the results (i.e., cells
`C1:C22`

)
and do “Conditional Formatting” → “New Rule”.
Select “use a formula to determine which cells to format”,
enter formula `=A1=A2`

, and format the cell to be invisible.
(Common ways of doing this are to set the font color to white
or to apply a custom number format of `;;;`

.)

In case the above isn’t clear:
This puts a number in every cell in the range,
but just hides the ones you don’t want.

### 2. Helper Column

- Pick a column that’s out of the way; for example, column
`Z`

.
Define it the same as we defined column `C`

, above.
- Set
`C1`

to `=IF(A1=A2, "", Z1)`

and drag/fill down to `C22`

.

### 3. All-in-One

- Set
`C1`

to `=IF(A1=A2, "", SUMIF(A$1:A$22, A1, B$1:$B22))`

and drag/fill down to `C22`

.

Note that, if the phone numbers are not sorted properly,
and are not divided into unique groups,
these methods produce different results.
Labeling the methods as follows:

- Conditional Formatting
- Helper Column
- All-in-One

consider these data:

```
phone value method1 method2 method3
︙ ︙ ︙ ︙ ︙
95 800 1500 1500 1500
42 1 ← First block of data for phone # 42
42 2 3 3 99 ← Note that methods 1 and 2 yield 1 + 2 = 3
17 4 ↖ but method 3 yields 1 + 2 + 32 + 64 = 99
17 8
17 16 28 28 28
42 32 ← Second block of data for phone # 42
42 64 96 96 99 ← Note that methods 1 and 2 yield 32 + 64 = 96
83 1000 ↖ but method 3 yields 1 + 2 + 32 + 64 = 99
83 2000 (again)
83 4000 7000 7000 7000
︙ ︙
```